Susumu Takahashi - DEV Community

Susumu Takahashi

Sep 29

pip Version Specifiers — What `==`, `>=`, and `~=` Actually Commit You To

#python #webdev #programming

1

4 min read

Susumu Takahashi

Sep 27

Cache-Control vs. ETag: What Each One Actually Controls

#wordpress #php #tutorial

1

4 min read

Susumu Takahashi

Sep 26

Exponential Backoff vs. Fixed-Interval Retries: When Growing Wait Times Actually Help

#python #webdev #programming

3

5 min read

Susumu Takahashi

Sep 24

Why SSH Key Authentication Beats Password Authentication — What Is Actually Being Proven

#wordpress #php #tutorial

2

1

4 min read

Susumu Takahashi

Sep 24

Unit Tests vs. Regression Tests: Why the Same Feature Gets Tested Twice

#python #webdev #programming

2

5 min read

Susumu Takahashi

Sep 22

How Desktop Apps Detect and Kill Stale Processes on Startup

#python #webdev #programming

2

1

5 min read

Susumu Takahashi

Sep 20

Semantic Versioning (SemVer): Why Version Numbers Have Three Parts

#python #webdev #programming

1

4 min read

Susumu Takahashi

Sep 19

How Symmetric Encryption (Fernet) Keeps Local Credentials Safe on Disk

#python #webdev #programming

1

5 min read

Susumu Takahashi

Sep 18

What `rsync -avz --delete` Actually Does

#wordpress #php #tutorial

2

4 min read

Susumu Takahashi

Sep 17

HTTP Status Code Basics: What 200/301/403/500 Actually Mean for Maintenance Tools

#wordpress #php #tutorial

1

4 min read

Susumu Takahashi

Sep 16

Reading `.htaccess` mod_rewrite Rules: A Real `RewriteBase` Trap From a Subdomain Migration

#wordpress #php #tutorial

1

4 min read

Susumu Takahashi

Sep 15

wp-config.php Key Constants Explained: What WP_DEBUG, DISALLOW_FILE_EDIT, and WP_MEMORY_LIMIT Actually Do

#wordpress #php #tutorial

1

4 min read

Susumu Takahashi

Sep 14

WordPress REST API Basics: What Can You Do With `/wp-json/`?

#wordpress #php #tutorial

1

5 min read

Susumu Takahashi

Sep 12

What Is Visual Regression Testing? How Screenshot Diffing Catches Layout Breaks

#python #webdev #programming

1

5 min read

Susumu Takahashi

Sep 11

What are PyInstaller "hidden imports" — and why do only dynamic imports break?

#python #webdev #programming

1

4 min read

Susumu Takahashi

Sep 9

Code signing basics — what Apple Notarization and Windows Authenticode actually certify

#python #webdev #programming

1

4 min read

Susumu Takahashi

Sep 9

Running Flask's dev server as a desktop app's backend — what actually matters

#python #webdev #programming

1

6 min read

Susumu Takahashi

Sep 8

Atomic writes — how tempfile + os.replace prevent corrupted JSON

#python #webdev #programming

2

5 min read

Susumu Takahashi

Sep 7

Cross-platform file locking in Python — fcntl vs msvcrt from scratch

#python #webdev #programming

1

5 min read

Susumu Takahashi

Sep 5

Crontab syntax basics, and how it differs from WP-Cron

#wordpress #php #tutorial

2

4 min read

Susumu Takahashi

Sep 4

Organizing per-host settings with `~/.ssh/config` — a standard practice for anyone managing multiple servers

#wordpress #php #tutorial

1

4 min read

Susumu Takahashi

Sep 3

SSH key types (RSA / ED25519 / ECDSA) — what actually differs, and which one to pick

#wordpress #php #tutorial

2

4 min read

Susumu Takahashi

Sep 2

How the WordPress transient API works, and when `wp transient delete` actually helps

#wordpress #php #tutorial

2

4 min read

Susumu Takahashi

Sep 1

`wp db check` / `wp db optimize` — the database health commands that get overlooked

#wordpress #php #tutorial

2

3 min read

Susumu Takahashi

Aug 31

Using WP-CLI aliases to switch between multiple WordPress environments safely

#wordpress #php #tutorial

1

2

4 min read

Susumu Takahashi

Aug 28

Comparing pricing models across four WordPress maintenance tools — what the shape of a price reveals about cost structure

#wordpress #php #tutorial

2

1

4 min read

Susumu Takahashi

Aug 28

A tabbed form that silently refused to submit — required fields hidden behind another tab

#python #webdev #programming

8

10

4 min read

Susumu Takahashi

Aug 27

UTF-8 vs. cp932: Why Some Bugs Only Show Up on Japanese Windows

#python #webdev #programming

2

4 min read

Susumu Takahashi

Aug 25

Verifying a WordPress major upgrade — a 7-step post-upgrade checklist

#wordpress #php #tutorial

2

6 min read

Susumu Takahashi

Aug 24

Greedy vs. Non-Greedy Regex: Why the Same Pattern Can Match Differently

#python #webdev #programming

2

5 min read

Susumu Takahashi

Aug 23

Log Level Design and Rotation: Why Apps Use DEBUG/INFO/WARNING/ERROR

#python #webdev #programming

1

5 min read

Susumu Takahashi

Aug 22

Site list scrolls to top on every delete — fixing the missing keepScroll argument across 6 call sites

#python #webdev #programming

1

2 min read

Susumu Takahashi

Aug 21

The Principle of Least Privilege: Why File Permissions Like 600/644/755 Exist

#python #webdev #programming

1

5 min read

Susumu Takahashi

Aug 20

The excluded-plugin setting that Playwright ignored — fixing browser-mode updates and false residual warnings

#wordpress #php #tutorial

1

3 min read

Susumu Takahashi

Aug 19

The cp932 crash in the build gate that only happened on Windows — static detection, behavioral testing, and a negative check

#python #webdev #programming

1

3 min read

Susumu Takahashi

Aug 18

Placing corrections exactly where an LLM is tempted to sound plausible instead of right

#python #webdev #programming

1

3 min read

Susumu Takahashi

Aug 17

A support chatbot needs to be designed for what it won't answer, not just what it will

#python #webdev #programming

1

2 min read

Susumu Takahashi

Aug 15

The free plan wasn't actually "no registration required" — fixing a landing page claim that contradicted itself

#python #webdev #programming

2

1

3 min read

Susumu Takahashi

Aug 13

Resuming email verification after the app is closed — the pending_email state that prevents re-sending

#python #webdev #programming

1

4 min read

Susumu Takahashi

Aug 13

SPF, DKIM, and DMARC together — why the missing DMARC record was blocking registration emails

#python #webdev #programming

1

3 min read

Susumu Takahashi

Aug 12

When maintenance ends with an error, the plugin update badge disappears — designing a backend marker and frontend count sync

#python #webdev #programming

2

4 min read

Susumu Takahashi

Aug 10

A csh bug we thought we fixed came back in a new feature — designing a login-shell-independent SSH command wrapper

#wordpress #php #tutorial

1

4 min read

Susumu Takahashi

Aug 9

Deploying and committing to git are not the same "done" — the trap of assuming uploaded means synced

#python #webdev #programming

1

3 min read

Susumu Takahashi

Aug 7

Checking that a count didn't change — a sanity check before writing a reorder API's result

#python #webdev #programming

1

3 min read

Susumu Takahashi

Aug 5

A version bump that got left behind — fixing it with a single source of truth and a `--check` gate

#python #webdev #programming

1

4 min read

Susumu Takahashi

Aug 5

Don't show users a raw Playwright error — translating exceptions into friendly messages

#wordpress #php #tutorial

1

3 min read

Susumu Takahashi

Aug 4

When "select all" checkboxes don't actually select anything — verifying after `check()`, not just trusting it

#wordpress #php #tutorial

1

3 min read

Susumu Takahashi

Aug 3

When `update-core.php` version scraping goes wrong — telling a plugin version number apart from WordPress core

#wordpress #php #tutorial

1

3 min read

Susumu Takahashi

Jul 31

Browser-based updates getting stuck on the "Confirm your admin email" screen — why Playwright stalls in wp-admin

#wordpress #php #tutorial

1

3 min read

Susumu Takahashi

Jul 30

Why scheduled posts don't publish on time — inspecting WP-Cron with WP-CLI

#wordpress #php #tutorial

1

3 min read

Susumu Takahashi

Jul 29

Locked out of wp-admin? Why WP-CLI works when `wp-login.php` doesn’t

#wordpress #php #tutorial

1

4 min read

Susumu Takahashi

Jul 28

Why phpMyAdmin migrations break plugin settings — and why `wp search-replace` doesn’t

#wordpress #php #tutorial

1

4 min read

Susumu Takahashi

Jul 24

Getting ready for WordPress 7.0 — three things to check now: PHP requirements, FSE migration, and editor extensions

#wordpress #php #tutorial

2

5 min read

Susumu Takahashi

Jul 23

Running a WordPress major upgrade step by step with WP-CLI — commands and checkpoints for each stage

#wordpress #php #tutorial

1

6 min read

Susumu Takahashi

Jul 22

Three site-list UX improvements: instant completion feedback, error highlighting, and auto-deselect

#python #webdev #programming

1

3 min read

Susumu Takahashi

Jul 21

Why environment variables don’t suppress WP-CLI PHP Deprecated warnings — the phar + shebang path and a three-part structural fix

#python #webdev #programming

4 min read

Susumu Takahashi

Jul 18

When SSH to Xserver suddenly stops working, it's fail2ban — the official confirmation and a safer reconnection check

#wordpress #php #tutorial

3 min read

Susumu Takahashi

Jul 16

Five failure patterns from past WordPress major upgrades — what 5.0 Gutenberg through 6.0 FSE taught maintenance teams

#wordpress #php #tutorial

5 min read

Susumu Takahashi

Jul 16

Don't apply WordPress major releases on day one — the "x.0.1 rule" and a calibration framework

#wordpress #php #tutorial

4 min read

Susumu Takahashi

Jul 15

Seven things to check before a WordPress major upgrade — before "patch what breaks after" becomes a disaster

#wordpress #php #tutorial

5 min read

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