Notes, experiments, and useful details from a little corner of the internet.https://nhancv.com/https://nhancv.com/garden/erc-4337-local-environment/https://nhancv.com/garden/erc-4337-local-environment/A small account-abstraction experiment: a local chain, a bundler, a mock paymaster, and a Safe smart account.Sat, 31 May 2025 04:18:38 GMThttps://nhancv.com/garden/create-and-create2/https://nhancv.com/garden/create-and-create2/Creation bytecode, constructor arguments, and the difference between a sender nonce and a deterministic deployment salt.Sat, 31 May 2025 02:57:53 GMThttps://nhancv.com/garden/send-dogecoin-testnet-transaction/https://nhancv.com/garden/send-dogecoin-testnet-transaction/An older TypeScript PSBT experiment with derivation, P2PKH inputs, fee estimates, and broadcast handling.Tue, 20 May 2025 03:52:57 GMThttps://nhancv.com/garden/setup-cometbft-pos-ethereum-private-chain-with-evmos-on-docker/https://nhancv.com/garden/setup-cometbft-pos-ethereum-private-chain-with-evmos-on-docker/A historical Evmos CLI 20.0.0 experiment with single-node, multi-node, explorer, and monitoring roles.Tue, 29 Oct 2024 11:22:35 GMThttps://nhancv.com/garden/setup-ibft-2-0-poa-ethereum-private-chain-with-besu-on-aws-cloud-via-terraform/https://nhancv.com/garden/setup-ibft-2-0-poa-ethereum-private-chain-with-besu-on-aws-cloud-via-terraform/An older IBFT 2.0 infrastructure notebook, with genesis identity, validator health, and storage estimates separated.Sun, 27 Oct 2024 08:55:38 GMThttps://nhancv.com/garden/libp2p-error-error-err-package-path-not-exported-no-exports-main-defined-in/https://nhancv.com/garden/libp2p-error-error-err-package-path-not-exported-no-exports-main-defined-in/An older libp2p loading workaround, with export maps, runtime evaluation, and stream lifetime kept distinct.Sun, 27 Oct 2024 05:49:43 GMThttps://nhancv.com/garden/ensuring-contract-callers-implement-a-custom-interface-in-solidity-using-erc165-without-openzeppelin/https://nhancv.com/garden/ensuring-contract-callers-implement-a-custom-interface-in-solidity-using-erc165-without-openzeppelin/Why a contract claiming an interface cannot prove that it is the caller your target intended to trust.Sun, 27 Oct 2024 05:07:20 GMThttps://nhancv.com/garden/proof-of-authority-poa-and-proof-of-stake-pos/https://nhancv.com/garden/proof-of-authority-poa-and-proof-of-stake-pos/Compare membership, economic weight, governance, and finality without inferring them from a label alone.Sun, 27 Oct 2024 03:11:40 GMThttps://nhancv.com/garden/ibft-ibft2-0-poa/https://nhancv.com/garden/ibft-ibft2-0-poa/Correcting an earlier comparison that incorrectly described original IBFT as having no rounds or leader changes.Sun, 27 Oct 2024 03:01:46 GMThttps://nhancv.com/garden/bitcoin-psbt-custom-utxos/https://nhancv.com/garden/bitcoin-psbt-custom-utxos/A historical BitcoinJS experiment covering four address families, fee estimation, and explicit input selection.Thu, 04 Jan 2024 06:41:25 GMThttps://nhancv.com/garden/send-a-btc-bitcoin-transaction-with-bitcoinjs-psbt/https://nhancv.com/garden/send-a-btc-bitcoin-transaction-with-bitcoinjs-psbt/An older four-address-type sender, with input data, fee estimation, address validation, and broadcast limits explicit.Thu, 04 Jan 2024 06:39:16 GMThttps://nhancv.com/garden/send-a-btc-bitcoin-transaction-from-both-a-legacy-p2pkh-address-and-a-native-segwit-p2wpkh-address-using-blockcypher/https://nhancv.com/garden/send-a-btc-bitcoin-transaction-from-both-a-legacy-p2pkh-address-and-a-native-segwit-p2wpkh-address-using-blockcypher/Transaction proposal, local signing, and broadcast are separate trust boundaries in this older Bitcoin example.Wed, 03 Jan 2024 07:39:38 GMThttps://nhancv.com/garden/bitcoin-extract-wallet-address-from-a-wif-private-key/https://nhancv.com/garden/bitcoin-extract-wallet-address-from-a-wif-private-key/A bitcoinjs-lib 6.1.5-era example for P2PKH, nested SegWit, native SegWit, and Taproot.Wed, 03 Jan 2024 07:34:57 GMThttps://nhancv.com/garden/blast-l2-airdrop-early-access/https://nhancv.com/garden/blast-l2-airdrop-early-access/Keeping the context of an old Blast promotion without carrying forward referral codes or deposit instructions.Sat, 25 Nov 2023 03:27:13 GMThttps://nhancv.com/garden/webpack-build-babel-loader-error-parsing-some-typescript-es-lib-module-parse-failed-unexpected-token/https://nhancv.com/garden/webpack-build-babel-loader-error-parsing-some-typescript-es-lib-module-parse-failed-unexpected-token/An older WalletConnect build failure around optional chaining and a narrowly scoped esbuild-loader rule.Fri, 21 Jul 2023 07:01:45 GMThttps://nhancv.com/garden/nginx-redirect-domain-config/https://nhancv.com/garden/nginx-redirect-domain-config/An older Nginx redirect fragment, with DNS, redirect response, and HTTPS validation separated.Fri, 21 Jul 2023 06:52:52 GMThttps://nhancv.com/garden/coinbase-base-network-vs-arbitrum/https://nhancv.com/garden/coinbase-base-network-vs-arbitrum/Keep architecture, transaction cost, inclusion latency, and finality as separate comparison questions.Fri, 21 Jul 2023 05:14:00 GMThttps://nhancv.com/garden/pancakeswap-uniswapv2-arbitrum-goerli-nitro-rollup-testnet/https://nhancv.com/garden/pancakeswap-uniswapv2-arbitrum-goerli-nitro-rollup-testnet/A historical Uniswap V2-style experiment, with chain identity and deployment constants kept together.Fri, 24 Feb 2023 06:31:17 GMThttps://nhancv.com/garden/custom-truffle-web3-provider-to-support-infura-authentication/https://nhancv.com/garden/custom-truffle-web3-provider-to-support-infura-authentication/Historical Web3 1.7.4 HTTP/WebSocket and Truffle fragments, with credential and provider-shape defects explicit.Wed, 19 Oct 2022 06:39:17 GMThttps://nhancv.com/garden/secure-infura-project-key/https://nhancv.com/garden/secure-infura-project-key/A historical Infura authentication note covering Basic auth, JWT claims, and where signing material belongs.Wed, 19 Oct 2022 06:29:12 GMThttps://nhancv.com/garden/google-sheets-api/https://nhancv.com/garden/google-sheets-api/An older service-account example with document sharing, range semantics, and error propagation made explicit.Tue, 18 Oct 2022 05:37:12 GMThttps://nhancv.com/garden/how-fast-to-take-aws-certificates/https://nhancv.com/garden/how-fast-to-take-aws-certificates/A learning sequence from an older certification note, without credential profiles or speed-to-pass claims.Tue, 19 Apr 2022 15:11:02 GMThttps://nhancv.com/garden/solidity-smart-contract-convention-x/https://nhancv.com/garden/solidity-smart-contract-convention-x/An older repository layout and formatting workflow, separated from compiler behavior and security guarantees.Mon, 14 Mar 2022 15:17:17 GMThttps://nhancv.com/garden/three-tier-aws-architecture/https://nhancv.com/garden/three-tier-aws-architecture/An older Terraform experiment in separating frontend, backend, and data access across two Availability Zones.Sat, 08 Jan 2022 08:20:13 GMThttps://nhancv.com/garden/how-to-config-redirect-root-naked-route53-domain-http-to-www-https-using-s3-and-cloudfront-with-route53/https://nhancv.com/garden/how-to-config-redirect-root-naked-route53-domain-http-to-www-https-using-s3-and-cloudfront-with-route53/Separate the redirect origin, viewer certificate, and DNS alias in an older AWS setup.Mon, 13 Dec 2021 07:41:50 GMThttps://nhancv.com/garden/solana-network-programming/https://nhancv.com/garden/solana-network-programming/A Solana 1.9 and Anchor 0.19 notebook about architecture mismatches and a local validator failure.Sat, 11 Dec 2021 15:00:16 GMThttps://nhancv.com/garden/multicall-smartcontract-js-client/https://nhancv.com/garden/multicall-smartcontract-js-client/Two older JavaScript watcher examples, with block consistency, polling lifetime, and numeric precision in view.Fri, 10 Dec 2021 06:57:02 GMThttps://nhancv.com/garden/verify-smart-contract-request-with-multi-signature-approach/https://nhancv.com/garden/verify-smart-contract-request-with-multi-signature-approach/Typed request fields and domain separation, with the historical quorum and replay defects left explicit.Fri, 15 Oct 2021 09:20:40 GMThttps://nhancv.com/garden/solidity-get-interface-id-and-erc165/https://nhancv.com/garden/solidity-get-interface-id-and-erc165/Function selectors, interface discovery, and why a support response is a capability claim rather than proof.Wed, 15 Sep 2021 09:16:41 GMThttps://nhancv.com/garden/about-smart-contract/https://nhancv.com/garden/about-smart-contract/An older presenter-contract experiment and the authority, state, and migration boundaries it introduces.Sun, 22 Aug 2021 05:33:58 GMThttps://nhancv.com/garden/about-dividend-token/https://nhancv.com/garden/about-dividend-token/An older reflection-token note, separated into accrual, conversion, and bounded distribution work.Sun, 22 Aug 2021 04:09:27 GMThttps://nhancv.com/garden/host-your-own-pancakeswap-testnet/https://nhancv.com/garden/host-your-own-pancakeswap-testnet/Keep the factory, router, pair bytecode hash, SDK, and frontend on the same deployment record.Sat, 17 Jul 2021 14:00:35 GMThttps://nhancv.com/garden/install-zabbix-server-monitor/https://nhancv.com/garden/install-zabbix-server-monitor/A historical Zabbix 5.4 and Ubuntu 20.04 setup, organized around the roles of each component.Tue, 06 Jul 2021 08:09:12 GMThttps://nhancv.com/garden/smart-contract-pagination-for-list/https://nhancv.com/garden/smart-contract-pagination-for-list/A Solidity 0.8.3 experiment showing why a view call can still exceed execution or response limits.Mon, 28 Jun 2021 07:50:45 GMThttps://nhancv.com/garden/mongodb-replica-setup/https://nhancv.com/garden/mongodb-replica-setup/Reworking a MongoDB 4.4 notebook around topology, reachable member names, and connection discovery.Mon, 28 Jun 2021 06:40:32 GMThttps://nhancv.com/garden/node-app-with-pm2-cluster/https://nhancv.com/garden/node-app-with-pm2-cluster/An older ecosystem configuration for two Node workers, with readiness, shutdown, and shared-state assumptions.Mon, 28 Jun 2021 06:18:15 GMThttps://nhancv.com/garden/nginx-http-load-balancer/https://nhancv.com/garden/nginx-http-load-balancer/Two local backends, weighted routing, and the boundaries around proxy headers and health checks.Mon, 28 Jun 2021 06:10:03 GMThttps://nhancv.com/garden/web-stress-test-with-jmeter/https://nhancv.com/garden/web-stress-test-with-jmeter/A historical JMeter 5.4.1 plan with thread settings, response assertions, and separate result artifacts.Mon, 28 Jun 2021 05:43:00 GMThttps://nhancv.com/garden/flutter-uplifting-daily-routines-rituals-self-control/https://nhancv.com/garden/flutter-uplifting-daily-routines-rituals-self-control/A historical product interaction centered on task lists, reminders, and per-step timers.Mon, 28 Jun 2021 05:06:46 GMThttps://nhancv.com/garden/smartcontract-ico-crowdsale-simple/https://nhancv.com/garden/smartcontract-ico-crowdsale-simple/An old Solidity experiment that changes a token conversion rate across a fixed sale window.Wed, 05 May 2021 02:59:56 GMThttps://nhancv.com/garden/voting-application-using-smart-contract/https://nhancv.com/garden/voting-application-using-smart-contract/A Solidity 0.4.21 demo and three ways to connect a UI, signer, and event listener.Wed, 05 May 2021 02:59:06 GMThttps://nhancv.com/garden/issue-your-erc20-token-with-solidity-on-ethereum-blockchain/https://nhancv.com/garden/issue-your-erc20-token-with-solidity-on-ethereum-blockchain/Contract compilation, wallet deployment, source verification, and explorer indexing from an older testnet walkthrough.Wed, 05 May 2021 02:50:28 GMThttps://nhancv.com/garden/upgrade-mongodb-from-3-6-3-to-4-4-4/https://nhancv.com/garden/upgrade-mongodb-from-3-6-3-to-4-4-4/Backup, installation, restore, and application verification are separate recovery steps.Wed, 07 Apr 2021 04:16:43 GMThttps://nhancv.com/garden/stacking-strategy-with-a-fair-reward-distribution/https://nhancv.com/garden/stacking-strategy-with-a-fair-reward-distribution/Three design objectives from an earlier fixed-pool staking idea, without treating them as proven guarantees.Sun, 04 Apr 2021 13:38:33 GMThttps://nhancv.com/garden/cryptocurrencies-deal-with-a-pending-transaction/https://nhancv.com/garden/cryptocurrencies-deal-with-a-pending-transaction/Correcting an older Bitcoin/Ethereum troubleshooting note around node visibility, nonce replacement, and confirmation.Tue, 02 Mar 2021 01:35:33 GMThttps://nhancv.com/garden/flutter-observer-pattern/https://nhancv.com/garden/flutter-observer-pattern/A shared subject and provider-scoped access, with subscription lifetime visible in the widget.Wed, 24 Feb 2021 16:50:31 GMThttps://nhancv.com/garden/flutter-mux-live-stream-rtmp-hls-m3u8/https://nhancv.com/garden/flutter-mux-live-stream-rtmp-hls-m3u8/Separate stream publication, playlist delivery, player initialization, and controls.Tue, 23 Feb 2021 07:04:03 GMThttps://nhancv.com/garden/import-lastpass-csv-format-to-keychain/https://nhancv.com/garden/import-lastpass-csv-format-to-keychain/An earlier browser-mediated import sequence, with the plaintext export boundary kept explicit.Tue, 23 Feb 2021 04:39:46 GMThttps://nhancv.com/garden/flutter-fullscreen-mode/https://nhancv.com/garden/flutter-fullscreen-mode/Hiding system overlays on entry and restoring a state on disposal in an earlier API.Mon, 22 Feb 2021 08:05:13 GMThttps://nhancv.com/garden/flutter-app-lifecycle-note/https://nhancv.com/garden/flutter-app-lifecycle-note/An earlier observation of inactive, paused, and resumed transitions.Mon, 22 Feb 2021 08:04:34 GMThttps://nhancv.com/garden/flutter-ci-with-bitrise/https://nhancv.com/garden/flutter-ci-with-bitrise/Separate build steps, signing, distribution, and notifications in a historical Android/iOS pipeline.Sat, 06 Feb 2021 15:35:11 GMThttps://nhancv.com/garden/flutter-custom-painter-rounded-rect-and-arrow/https://nhancv.com/garden/flutter-custom-painter-rounded-rect-and-arrow/A small CustomPainter experiment that joins a rounded rectangle and a triangular pointer.Thu, 28 Jan 2021 09:27:27 GMThttps://nhancv.com/garden/flutter-search-highlight-text-widget/https://nhancv.com/garden/flutter-search-highlight-text-widget/An older RichText example that separates filtering records from marking matching spans.Wed, 27 Jan 2021 05:51:53 GMThttps://nhancv.com/garden/macbook-m1-ntfs-photoshop/https://nhancv.com/garden/macbook-m1-ntfs-photoshop/A small historical record that should not be mistaken for a current software or pricing recommendation.Tue, 26 Jan 2021 07:41:51 GMThttps://nhancv.com/garden/macbook-m1-flutter-error/https://nhancv.com/garden/macbook-m1-flutter-error/Several historical M1 failures involving filtering software, IDE discovery, native Ruby extensions, and debugger logs.Tue, 26 Jan 2021 07:29:34 GMThttps://nhancv.com/garden/macbook-pro-m1-homebrew-install-error/https://nhancv.com/garden/macbook-pro-m1-homebrew-install-error/The difference between a Rosetta process and an ARM Homebrew prefix in an older M1 setup.Tue, 26 Jan 2021 07:20:37 GMThttps://nhancv.com/garden/flutter-hide-widget-when-keyboard-opened/https://nhancv.com/garden/flutter-hide-widget-when-keyboard-opened/An older wrapper that separates invisible-but-laid-out content from a removed subtree.Fri, 15 Jan 2021 11:24:39 GMThttps://nhancv.com/garden/flutter-pusher-with-npusher/https://nhancv.com/garden/flutter-pusher-with-npusher/A historical Flutter example for Echo-style events, authorization headers, and periodic presence updates.Fri, 15 Jan 2021 03:29:02 GMThttps://nhancv.com/garden/flutter-circle-image-cropping-draggable/https://nhancv.com/garden/flutter-circle-image-cropping-draggable/An older overlay and capture implementation with distinct display, geometry, and output-file boundaries.Thu, 14 Jan 2021 17:26:50 GMThttps://nhancv.com/garden/flutter-insert-text-to-textfield/https://nhancv.com/garden/flutter-insert-text-to-textfield/A small historical TextEditingController update and the selection cases it does not cover.Fri, 08 Jan 2021 15:36:48 GMThttps://nhancv.com/garden/flutter-sqflite-persist-data-with-sqlite/https://nhancv.com/garden/flutter-sqflite-persist-data-with-sqlite/Versioned schema changes, repositories, database lifetime, and local-store access from an earlier Flutter example.Fri, 08 Jan 2021 15:26:14 GMThttps://nhancv.com/garden/flutter-custom-icon-fonts/https://nhancv.com/garden/flutter-custom-icon-fonts/An earlier SVG-to-font workflow and three small text/controller experiments.Fri, 08 Jan 2021 15:23:54 GMThttps://nhancv.com/garden/flutter-pusher-with-laravel-echo/https://nhancv.com/garden/flutter-pusher-with-laravel-echo/Connection state, event namespaces, and authorization roles in a historical Flutter example.Fri, 08 Jan 2021 15:20:36 GMThttps://nhancv.com/garden/flutter-api-persists-the-cookies-in-files-custom-x-csrf-token-csrf-cookie-xsrf-token/https://nhancv.com/garden/flutter-api-persists-the-cookies-in-files-custom-x-csrf-token-csrf-cookie-xsrf-token/The relationship between a stored session cookie, an XSRF header, and asynchronous client initialization.Fri, 08 Jan 2021 13:20:03 GMThttps://nhancv.com/garden/flutter-image-picker/https://nhancv.com/garden/flutter-image-picker/Permission descriptions, source selection, cancellation, and the application's avatar-upload boundary.Sun, 13 Dec 2020 04:19:09 GMThttps://nhancv.com/garden/flutter-firebase-service/https://nhancv.com/garden/flutter-firebase-service/A historical collection spanning native setup, authentication, storage, functions, messaging, local notifications, and telemetry.Sun, 13 Dec 2020 04:14:14 GMThttps://nhancv.com/garden/open-multi-urls-in-chrome-macos/https://nhancv.com/garden/open-multi-urls-in-chrome-macos/An earlier shell loop for launching several known destinations through the application launcher.Sun, 13 Dec 2020 03:40:10 GMThttps://nhancv.com/garden/flutter-iap-subscription-config/https://nhancv.com/garden/flutter-iap-subscription-config/Product identity, native billing configuration, and sandbox evidence from a historical purchase integration.Sun, 13 Dec 2020 03:28:24 GMThttps://nhancv.com/garden/android/https://nhancv.com/garden/android/Native launch resources from an older Flutter host project, without importing archive attachments.Sun, 13 Dec 2020 03:08:11 GMThttps://nhancv.com/garden/flutter-datetime-format/https://nhancv.com/garden/flutter-datetime-format/Formatting examples and the calendar assumptions hidden in today, yesterday, week, and elapsed-time checks.Sun, 13 Dec 2020 02:59:39 GMThttps://nhancv.com/garden/upload-file-with-expressjs-and-multer-javascript/https://nhancv.com/garden/upload-file-with-expressjs-and-multer-javascript/Disk storage, one-file and named-field uploads, and the validation missing from a small demonstration.Sun, 13 Dec 2020 02:56:13 GMThttps://nhancv.com/garden/habitapp-habit-trackertimer/https://nhancv.com/garden/habitapp-habit-trackertimer/A historical product note about grouping routine steps and giving each step a visible timer.Fri, 25 Sep 2020 03:58:14 GMThttps://nhancv.com/garden/flutter-current-route-active-tracking-debug/https://nhancv.com/garden/flutter-current-route-active-tracking-debug/A RouteObserver-based mixin that separates screen activation from application lifecycle events.Wed, 09 Sep 2020 17:29:05 GMThttps://nhancv.com/garden/flutter-track-applifecyclestate-debug/https://nhancv.com/garden/flutter-track-applifecyclestate-debug/An older WidgetsBindingObserver example and the distinction between app visibility and route visibility.Wed, 09 Sep 2020 17:10:31 GMThttps://nhancv.com/garden/flutter-widget-life-cycle-debug/https://nhancv.com/garden/flutter-widget-life-cycle-debug/An earlier parent-property experiment around initState, didUpdateWidget, build, and disposal.Wed, 09 Sep 2020 16:51:23 GMThttps://nhancv.com/garden/integrate-facebook-google-firebase-keyhash/https://nhancv.com/garden/integrate-facebook-google-firebase-keyhash/Distinguish local/upload certificates from the certificate that signs the application delivered by Play.Wed, 29 Jul 2020 15:52:18 GMThttps://nhancv.com/garden/flutter-java-lang-runtimeexception-java-lang-runtimeexception-duplicate-class/https://nhancv.com/garden/flutter-java-lang-runtimeexception-java-lang-runtimeexception-duplicate-class/An older Android dependency conflict between Guava and the standalone listenablefuture artifact.Wed, 29 Jul 2020 15:48:23 GMThttps://nhancv.com/garden/flutter-webrtc-build-android-release-error/https://nhancv.com/garden/flutter-webrtc-build-android-release-error/The JNI class-lookup error and keep rules recorded around an older Android shrinking configuration.Wed, 29 Jul 2020 15:45:33 GMThttps://nhancv.com/garden/flutter-ios-by-pass-permission-pop-up-on-emulator-integration-testing/https://nhancv.com/garden/flutter-ios-by-pass-permission-pop-up-on-emulator-integration-testing/An earlier AppleSimulatorUtils script that creates a dedicated simulator and sets test permissions.Fri, 17 Jul 2020 10:51:26 GMThttps://nhancv.com/garden/flutter-run-task-after-widget-render/https://nhancv.com/garden/flutter-run-task-after-widget-render/A small recorded lifecycle trace that distinguishes two scheduling boundaries.Thu, 16 Jul 2020 10:25:35 GMThttps://nhancv.com/garden/flutter-ios-release-build-error/https://nhancv.com/garden/flutter-ios-release-build-error/An older armv7-versus-arm64 linker report and the need to align the application target with its libraries.Wed, 01 Jul 2020 15:17:14 GMThttps://nhancv.com/garden/flutter-crashlytics-integration/https://nhancv.com/garden/flutter-crashlytics-integration/Native build hooks and separate framework, isolate, and zoned-error paths in a historical integration.Sat, 27 Jun 2020 17:11:32 GMThttps://nhancv.com/garden/flutter-analytics-integration/https://nhancv.com/garden/flutter-analytics-integration/A shared analytics object, route observer, and event example from older FlutterFire packages.Sat, 27 Jun 2020 16:29:34 GMThttps://nhancv.com/garden/flutter-create-a-firebase-project/https://nhancv.com/garden/flutter-create-a-firebase-project/Project registration and native configuration files for Android and iOS, kept separate from runtime initialization.Sat, 27 Jun 2020 15:57:14 GMThttps://nhancv.com/garden/simple-slide-up-widget-animation/https://nhancv.com/garden/simple-slide-up-widget-animation/Separate the panel's static layout, visibility state, controller, and animation.Sat, 27 Jun 2020 13:24:26 GMThttps://nhancv.com/garden/flutter-boilerplate-for-newbie/https://nhancv.com/garden/flutter-boilerplate-for-newbie/An earlier template's structure, localization, environment entry points, tests, and release preparation.Sat, 27 Jun 2020 09:59:02 GMThttps://nhancv.com/garden/flutter-socket-io/https://nhancv.com/garden/flutter-socket-io/Connection callbacks, a named event, and the assumptions hidden behind a simple socket interface.Sat, 27 Jun 2020 06:57:25 GMThttps://nhancv.com/garden/flutter-web-experiment/https://nhancv.com/garden/flutter-web-experiment/A LayoutBuilder-based sign-up screen and the limits of treating compiled output as a security boundary.Thu, 23 Apr 2020 10:23:05 GMThttps://nhancv.com/garden/flutter-ios-build-error-diagnose/https://nhancv.com/garden/flutter-ios-build-error-diagnose/A recorded simulator build failure and why dependency regeneration is different from changing an application's source.Thu, 16 Apr 2020 11:16:56 GMThttps://nhancv.com/garden/multiple-git-config/https://nhancv.com/garden/multiple-git-config/Conditional Git configuration without publishing real names, email addresses, or workstation paths.Tue, 14 Apr 2020 09:41:38 GMThttps://nhancv.com/garden/install-janus-webrtc-ubuntu-server-18-04-4/https://nhancv.com/garden/install-janus-webrtc-ubuntu-server-18-04-4/Dependencies, transports, local certificates, and demo boundaries from a historical Janus setup.Thu, 09 Apr 2020 03:42:16 GMThttps://nhancv.com/garden/flutter-integrate-onesignale-push-notification/https://nhancv.com/garden/flutter-integrate-onesignale-push-notification/Android, iOS, and Dart configuration roles in a historical OneSignal 2.3.4 integration.Wed, 25 Mar 2020 12:19:25 GMThttps://nhancv.com/garden/expressjs-on-netlify/https://nhancv.com/garden/expressjs-on-netlify/Two netlify-lambda directory arrangements and the difference between function output and a site's publish directory.Wed, 18 Mar 2020 14:10:18 GMThttps://nhancv.com/garden/protect-private-content-s3-using-aws-cloudfront/https://nhancv.com/garden/protect-private-content-s3-using-aws-cloudfront/An older signed-URL and signed-cookie experiment, rewritten around origin protection and viewer authorization.Sat, 14 Mar 2020 14:31:58 GMThttps://nhancv.com/garden/aws-s3-with-nodejs-practice/https://nhancv.com/garden/aws-s3-with-nodejs-practice/The distinction between storage operations, credentials, and public object access in an earlier SDK example.Wed, 11 Mar 2020 07:33:35 GMThttps://nhancv.com/garden/aws-sa-fundamentals/https://nhancv.com/garden/aws-sa-fundamentals/Shared responsibility, availability, recovery objectives, scaling, and infrastructure boundaries from an earlier AWS notebook.Wed, 11 Mar 2020 05:20:58 GMThttps://nhancv.com/garden/tech-convert-ppk-file-to-pem-for-ssh-to-ec2/https://nhancv.com/garden/tech-convert-ppk-file-to-pem-for-ssh-to-ec2/Historical Linux and macOS commands for changing a private key's file format without changing its purpose.Tue, 03 Mar 2020 07:06:04 GMThttps://nhancv.com/garden/create-trc20-token-on-tron-network-with-nodejs/https://nhancv.com/garden/create-trc20-token-on-tron-network-with-nodejs/Deployment, explorer registration, and token transfers are separate stages of this historical TronWeb example.Tue, 21 Jan 2020 05:48:47 GMThttps://nhancv.com/garden/create-trc10-token-on-tron-network-with-nodejs/https://nhancv.com/garden/create-trc10-token-on-tron-network-with-nodejs/The transaction-building, signing, and broadcast stages of a historical TronWeb experiment.Tue, 21 Jan 2020 04:41:07 GMThttps://nhancv.com/garden/ubuntu-enable-disable-service/https://nhancv.com/garden/ubuntu-enable-disable-service/A short reference separating running a service now from configuring whether it starts on boot.Tue, 24 Dec 2019 04:59:25 GMThttps://nhancv.com/garden/homebrew-reset-clean-remove-all-packages/https://nhancv.com/garden/homebrew-reset-clean-remove-all-packages/Three commands with different effects: removing installed packages, cleaning archives, and the earlier Cask syntax.Wed, 18 Dec 2019 07:39:05 GMThttps://nhancv.com/garden/windows-7-startup-program/https://nhancv.com/garden/windows-7-startup-program/The older per-user Startup-folder workflow for launching an application after sign-in.Wed, 18 Dec 2019 07:37:34 GMThttps://nhancv.com/garden/nodejs-logging/https://nhancv.com/garden/nodejs-logging/A shared logger import with rotating files, an environment label, and fixed-offset timestamps.Wed, 18 Dec 2019 07:36:50 GMThttps://nhancv.com/garden/flutter-transparent-ios-background-keyboard-when-it-open/https://nhancv.com/garden/flutter-transparent-ios-background-keyboard-when-it-open/An older Stack-based layout that kept a background behind a transparent Scaffold.Wed, 18 Dec 2019 04:51:50 GMThttps://nhancv.com/garden/flutter-base-model-approach/https://nhancv.com/garden/flutter-base-model-approach/A historical model-design note about shared error fields, typed data, and responses with different shapes.Fri, 06 Dec 2019 10:29:55 GMThttps://nhancv.com/garden/newbie-chapter-5-basic-tickets/https://nhancv.com/garden/newbie-chapter-5-basic-tickets/The fifth beginner chapter covers localization, data, navigation, versioning, testing, and profiling.Mon, 02 Dec 2019 05:12:58 GMThttps://nhancv.com/garden/flutter-detect-memory-pressure/https://nhancv.com/garden/flutter-detect-memory-pressure/An older binding observer and cache-clearing experiment, with its limits distinguished from an OOM diagnosis.Mon, 02 Dec 2019 04:32:29 GMThttps://nhancv.com/garden/create-a-wordpress-child-theme/https://nhancv.com/garden/create-a-wordpress-child-theme/An earlier child-theme setup and the need for the directory, parent template, and styles to agree.Tue, 26 Nov 2019 10:39:30 GMThttps://nhancv.com/garden/setup-a-simple-face-recognition/https://nhancv.com/garden/setup-a-simple-face-recognition/An Ubuntu/Python environment and a small Flask upload service, preserved with its deployment limits.Tue, 26 Nov 2019 08:34:07 GMThttps://nhancv.com/garden/install-zeebe/https://nhancv.com/garden/install-zeebe/Broker, workflow execution, and monitoring roles from an older local orchestration example.Tue, 26 Nov 2019 08:10:23 GMThttps://nhancv.com/garden/linux-multi-terminal/https://nhancv.com/garden/linux-multi-terminal/A small session, window, and pane reference for an older Linux terminal workflow.Tue, 26 Nov 2019 07:51:36 GMThttps://nhancv.com/garden/install-docker-on-ubuntu-18-10/https://nhancv.com/garden/install-docker-on-ubuntu-18-10/Repository codenames, container inspection, and the destructive cleanup commands in a historical setup.Tue, 26 Nov 2019 07:48:54 GMThttps://nhancv.com/garden/javascript-extract-info-from-regex/https://nhancv.com/garden/javascript-extract-info-from-regex/Extracting an amount and timestamp from a fixed four-line message format.Mon, 25 Nov 2019 16:22:35 GMThttps://nhancv.com/garden/generate-new-bitcoin-wallet-using-bitcoinjs/https://nhancv.com/garden/generate-new-bitcoin-wallet-using-bitcoinjs/Key generation, two address forms, and explorer lookups from an earlier testnet example.Sun, 24 Nov 2019 02:42:34 GMThttps://nhancv.com/garden/get-wallet-address-from-wif-with-bitcoinjs/https://nhancv.com/garden/get-wallet-address-from-wif-with-bitcoinjs/An older BitcoinJS example that chooses a network and constructs P2PKH and P2SH-P2WPKH payments.Sat, 23 Nov 2019 18:37:37 GMThttps://nhancv.com/garden/bitcoin-convert-private-key-to-wif/https://nhancv.com/garden/bitcoin-convert-private-key-to-wif/An older private-key encoding example, with network and compressed-public-key context.Sat, 23 Nov 2019 18:33:29 GMThttps://nhancv.com/garden/flutter-singleton-separate-approach/https://nhancv.com/garden/flutter-singleton-separate-approach/A small comparison between explicit instance access, ordinary construction, and a factory constructor.Thu, 21 Nov 2019 11:00:04 GMThttps://nhancv.com/garden/jenkins-fix-command-not-found/https://nhancv.com/garden/jenkins-fix-command-not-found/Inspect the execution environment rather than assuming the interactive shell and build share a PATH.Thu, 21 Nov 2019 09:26:46 GMThttps://nhancv.com/garden/flutter-onesignal-example-snipcode/https://nhancv.com/garden/flutter-onesignal-example-snipcode/Historical receive/open callbacks and player-ID access from the shared-instance API.Fri, 15 Nov 2019 07:32:59 GMThttps://nhancv.com/garden/newbie-chapter-4-widgets-state/https://nhancv.com/garden/newbie-chapter-4-widgets-state/The fourth beginner chapter separates widget configuration, State lifetime, app lifecycle, and stream-based updates.Tue, 12 Nov 2019 02:32:35 GMThttps://nhancv.com/garden/newbie-chapter-3-flutter-initial-setup/https://nhancv.com/garden/newbie-chapter-3-flutter-initial-setup/A historical third chapter covering telemetry integration, CI, signing, launcher icons, and native splash resources.Mon, 11 Nov 2019 08:07:49 GMThttps://nhancv.com/garden/newbie-chapter-2-flutter-getting-started/https://nhancv.com/garden/newbie-chapter-2-flutter-getting-started/The second beginner chapter connects toolchain checks, a first application, and consistent source organization.Sun, 10 Nov 2019 09:56:24 GMThttps://nhancv.com/garden/newbie-chapter-1-flutter-overview/https://nhancv.com/garden/newbie-chapter-1-flutter-overview/The first chapter of an earlier beginner series, rewritten around its core UI model.Sat, 09 Nov 2019 11:42:11 GMThttps://nhancv.com/garden/nginx-proxy-pass-config/https://nhancv.com/garden/nginx-proxy-pass-config/A reverse-proxy example whose invalid upstream address and mismatched enable path need correction before reuse.Sat, 09 Nov 2019 06:09:14 GMThttps://nhancv.com/garden/setup-wordpress-on-vps-php-nginx/https://nhancv.com/garden/setup-wordpress-on-vps-php-nginx/A retrospective on Nginx, PHP-FPM, MySQL, file ownership, backups, and certificate boundaries.Sat, 09 Nov 2019 05:55:22 GMThttps://nhancv.com/garden/ssl-free-with-certbot-and-nginx/https://nhancv.com/garden/ssl-free-with-certbot-and-nginx/The HTTP virtual-host and certificate workflow from an earlier Ubuntu deployment.Sat, 09 Nov 2019 05:31:57 GMThttps://nhancv.com/garden/wordpress-image-rotation-is-not-supported-by-your-web-host/https://nhancv.com/garden/wordpress-image-rotation-is-not-supported-by-your-web-host/The PHP GD package and PHP-FPM restart recorded for a previous host.Fri, 08 Nov 2019 17:24:08 GMThttps://nhancv.com/garden/android-obfuscate-code-with-proguard/https://nhancv.com/garden/android-obfuscate-code-with-proguard/Release minification, reflection metadata, and the dependency versions behind a historical setup.Thu, 07 Nov 2019 08:53:08 GMThttps://nhancv.com/garden/flutter-setstate/https://nhancv.com/garden/flutter-setstate/A nested-widget experiment that records build and lifecycle calls around several buttons.Thu, 07 Nov 2019 04:44:00 GMThttps://nhancv.com/garden/flutter-printer-and-cashdrawer/https://nhancv.com/garden/flutter-printer-and-cashdrawer/An older network-printer example, raw drawer commands, and a small printer-library extension.Thu, 07 Nov 2019 01:30:49 GMThttps://nhancv.com/garden/flutter-state-management-with-bloc-simple-approach/https://nhancv.com/garden/flutter-state-management-with-bloc-simple-approach/An older separation of input, loading, results, and asynchronous search logic.Tue, 05 Nov 2019 08:10:08 GMThttps://nhancv.com/garden/extract-data-by-regex-in-javascript/https://nhancv.com/garden/extract-data-by-regex-in-javascript/The difference between a full match and the substring captured between two delimiters.Tue, 05 Nov 2019 07:37:37 GMThttps://nhancv.com/garden/enable-virtualization-technology-in-bios/https://nhancv.com/garden/enable-virtualization-technology-in-bios/A short historical note on the firmware toggle behind hardware-assisted virtualization.Tue, 05 Nov 2019 07:37:10 GMThttps://nhancv.com/garden/hide-ip-with-proxy-on-macos/https://nhancv.com/garden/hide-ip-with-proxy-on-macos/An earlier proxy-settings experiment and the limits of checking only the visible public IP.Tue, 05 Nov 2019 07:36:31 GMThttps://nhancv.com/garden/the-diagnostic-centos-ip-address/https://nhancv.com/garden/the-diagnostic-centos-ip-address/Interface inspection, network-scripts files, and the effect of restarting the network service.Tue, 05 Nov 2019 07:33:22 GMThttps://nhancv.com/garden/postgresql-benchmark/https://nhancv.com/garden/postgresql-benchmark/Initialization, concurrent clients, and why two different benchmark workloads cannot be compared directly.Tue, 05 Nov 2019 07:26:09 GMThttps://nhancv.com/garden/flutter-hide-keyboard/https://nhancv.com/garden/flutter-hide-keyboard/An older focus-node and BLoC example for explicit keyboard dismissal around search and navigation.Tue, 05 Nov 2019 07:20:58 GMThttps://nhancv.com/garden/flutter-can-not-focus-on-the-textfield-after-navigation/https://nhancv.com/garden/flutter-can-not-focus-on-the-textfield-after-navigation/Why dismissing focus inside build can repeatedly undo a user's text-field interaction.Tue, 05 Nov 2019 07:16:16 GMThttps://nhancv.com/garden/flutter-offline-caching/https://nhancv.com/garden/flutter-offline-caching/An older stream-based cache pattern that distinguishes local display data from network results.Tue, 05 Nov 2019 07:14:07 GMThttps://nhancv.com/garden/hpz420-workstation-memory-training-error/https://nhancv.com/garden/hpz420-workstation-memory-training-error/A workstation boot error and the power-management settings recorded during the earlier investigation.Tue, 05 Nov 2019 07:06:37 GMThttps://nhancv.com/garden/rounded-textfield-flutter/https://nhancv.com/garden/rounded-textfield-flutter/A compact styling note on filled inputs, border radii, padding, and focus states.Tue, 05 Nov 2019 07:02:58 GMThttps://nhancv.com/garden/rename-file-in-dart/https://nhancv.com/garden/rename-file-in-dart/An older filesystem script that normalizes PNG names and moves @2x/@3x assets into scale directories.Tue, 05 Nov 2019 07:00:14 GMThttps://nhancv.com/garden/flutter-gesturedetector-tapping-is-not-working-in-containter/https://nhancv.com/garden/flutter-gesturedetector-tapping-is-not-working-in-containter/A small historical hit-testing fix, with the widget-tree assumptions kept visible.Tue, 05 Nov 2019 06:59:13 GMThttps://nhancv.com/garden/flutter-splash-screen/https://nhancv.com/garden/flutter-splash-screen/Android launch resources and first-layout cleanup from the original Flutter embedding.Tue, 05 Nov 2019 06:58:06 GMThttps://nhancv.com/garden/nodejs-dot-env/https://nhancv.com/garden/nodejs-dot-env/A small CommonJS example showing why configuration must load before it is read.Tue, 05 Nov 2019 06:55:04 GMThttps://nhancv.com/garden/heroku-deal-with-env/https://nhancv.com/garden/heroku-deal-with-env/A short note on separating application configuration from its source files.Tue, 05 Nov 2019 06:53:11 GMThttps://nhancv.com/garden/flutter-textfield-keyboard-sample/https://nhancv.com/garden/flutter-textfield-keyboard-sample/An older Scaffold and Android launch-theme example for a screen with several text fields.Tue, 05 Nov 2019 06:51:01 GMThttps://nhancv.com/garden/nginx-proxy-pass/https://nhancv.com/garden/nginx-proxy-pass/A small historical reverse-proxy example with forwarding and WebSocket-upgrade headers.Tue, 05 Nov 2019 03:53:53 GMThttps://nhancv.com/garden/nscancode/https://nhancv.com/garden/nscancode/A historical Android utility for QR codes and several one- and two-dimensional barcode formats.Mon, 04 Nov 2019 18:29:02 GMThttps://nhancv.com/garden/mongodb-v4-2-0-nodejs-get-started/https://nhancv.com/garden/mongodb-v4-2-0-nodejs-get-started/A callback-style connection snippet from a MongoDB 4.2-era note.Mon, 04 Nov 2019 18:23:33 GMThttps://nhancv.com/garden/nodejs-logging-with-winston-rotation-file-and-specific-timezone/https://nhancv.com/garden/nodejs-logging-with-winston-rotation-file-and-specific-timezone/An earlier logging configuration combining hourly filenames, retention limits, and formatted timestamps.Mon, 04 Nov 2019 18:21:50 GMThttps://nhancv.com/garden/android-support-gzip-file/https://nhancv.com/garden/android-support-gzip-file/An older file-compression helper and the resource-handling limits of its happy-path cleanup.Mon, 04 Nov 2019 18:19:56 GMThttps://nhancv.com/garden/android-working-with-byte/https://nhancv.com/garden/android-working-with-byte/An older conversion helper for numbers, offsets, and array slices.Mon, 04 Nov 2019 18:18:14 GMThttps://nhancv.com/garden/native-md5-nodejs/https://nhancv.com/garden/native-md5-nodejs/Two small crypto examples that perform different operations: an MD5 digest and an HMAC.Mon, 04 Nov 2019 18:16:59 GMThttps://nhancv.com/garden/export-firestore-database/https://nhancv.com/garden/export-firestore-database/Schema-directed collection traversal, with the original script's naming and export-shape limitations made visible.Mon, 04 Nov 2019 18:15:25 GMThttps://nhancv.com/garden/android-socket-io-client-v1-0-0-engineioexception-xhr-poll-error/https://nhancv.com/garden/android-socket-io-client-v1-0-0-engineioexception-xhr-poll-error/Separate transport timeouts, reverse-proxy upgrades, and certificate validation when diagnosing an old client.Mon, 04 Nov 2019 18:10:49 GMThttps://nhancv.com/garden/android-some-notes-for-android-java-jni-c-ndk/https://nhancv.com/garden/android-some-notes-for-android-java-jni-c-ndk/An older collection of CMake, native logging, bitmap, and Java-array boundary examples.Mon, 04 Nov 2019 18:07:28 GMThttps://nhancv.com/garden/android-rotate-yuv420-byte-data/https://nhancv.com/garden/android-rotate-yuv420-byte-data/Historical Java routines for 90-, 180-, and 270-degree rotation of a packed camera buffer.Mon, 04 Nov 2019 18:02:44 GMThttps://nhancv.com/garden/android-gradle-dsl-method-not-found-deleteallactions-anotation/https://nhancv.com/garden/android-gradle-dsl-method-not-found-deleteallactions-anotation/A short record of a Gradle upgrade conflict caused by an obsolete lambda backport plugin.Mon, 04 Nov 2019 17:59:57 GMThttps://nhancv.com/garden/what-difference-between-and-in-kotlin-see-below-table/https://nhancv.com/garden/what-difference-between-and-in-kotlin-see-below-table/A small comparison of direct access, safe calls, and the !! operator.Mon, 04 Nov 2019 17:58:03 GMThttps://nhancv.com/garden/detect-wifi-format-with-regex-in-kotlin/https://nhancv.com/garden/detect-wifi-format-with-regex-in-kotlin/A restricted WIFI payload parser and the capture groups used to read its fields.Mon, 04 Nov 2019 17:55:31 GMThttps://nhancv.com/garden/android-could-not-find-method-annotationprocessor-for-arguments/https://nhancv.com/garden/android-could-not-find-method-annotationprocessor-for-arguments/A recorded workaround for a build-script failure around the Android Gradle plugin 3 transition.Mon, 04 Nov 2019 17:54:41 GMThttps://nhancv.com/garden/telegram-bot/https://nhancv.com/garden/telegram-bot/The BotFather command sequence, group visibility, and the distinction between chat and sender identifiers.Mon, 04 Nov 2019 17:20:17 GMThttps://nhancv.com/garden/why-use-bind-in-javascript/https://nhancv.com/garden/why-use-bind-in-javascript/Why extracting a method changes its receiver, and how bind preserves the intended object.Mon, 04 Nov 2019 17:16:39 GMThttps://nhancv.com/garden/wifi-qr-code-generator/https://nhancv.com/garden/wifi-qr-code-generator/A compact note on the WIFI payload and the network credentials it contains.Mon, 04 Nov 2019 17:12:15 GMThttps://nhancv.com/garden/android-build-duplicate-libraries/https://nhancv.com/garden/android-build-duplicate-libraries/Use the Gradle dependency graph to locate duplicate classes before applying a narrow exclusion.Mon, 04 Nov 2019 17:09:57 GMThttps://nhancv.com/garden/android-modal-bottom-sheet-dialog/https://nhancv.com/garden/android-modal-bottom-sheet-dialog/An older Material bottom-sheet treatment using a drawable, dimensions, and dialog themes.Mon, 04 Nov 2019 17:06:24 GMThttps://nhancv.com/garden/android-screen-touch-test/https://nhancv.com/garden/android-screen-touch-test/An earlier utility that marks touch positions and uses the Back button to clear or exit.Mon, 04 Nov 2019 17:00:01 GMThttps://nhancv.com/garden/android-runtime-permissions/https://nhancv.com/garden/android-runtime-permissions/A historical permission-controller example, with explicit requests, result callbacks, and the limits of an all-permissions approach.Mon, 04 Nov 2019 16:53:57 GMThttps://nhancv.com/garden/deploy-smart-contract-with-truffle/https://nhancv.com/garden/deploy-smart-contract-with-truffle/A historical walkthrough of Ganache, environment-based wallet configuration, and Truffle migrations.Mon, 04 Nov 2019 16:31:42 GMT