Add comprehensive login page customization options #7374

strickvl · 2025-06-12T17:19:56Z

This PR adds comprehensive customization options for the login page, allowing users to customize all text elements through CLI arguments, environment variables, or config files.

🎯 Key Features

Complete login customization - Every text element can be customized
Multiple configuration methods - CLI args, environment variables, YAML config
Docker-friendly - Perfect for containerized deployments with env vars
Corporate branding - Customize titles, messages, and error text
Security-first - All user input is HTML-escaped to prevent XSS
Backwards compatible - Existing --app-name/--welcome-text unchanged

📋 New CLI Options

--login-title                      # Custom login page title
--login-below                      # Custom text below login title  
--password-placeholder             # Custom password field placeholder
--submit-text                      # Custom submit button text
--login-password-msg               # Custom config file password message
--login-env-password-msg           # Custom env password message
--login-hashed-password-msg        # Custom hashed password message
--login-rate-limit-msg             # Custom rate limiting message
--missing-password-msg             # Custom missing password error
--incorrect-password-msg           # Custom incorrect password error

🐳 Environment Variables

All CLI options have corresponding CS_* environment variables:

CS_LOGIN_TITLE, CS_LOGIN_BELOW, CS_PASSWORD_PLACEHOLDER, CS_SUBMIT_TEXT
CS_LOGIN_PASSWORD_MSG, CS_LOGIN_ENV_PASSWORD_MSG, CS_LOGIN_HASHED_PASSWORD_MSG  
CS_LOGIN_RATE_LIMIT_MSG, CS_MISSING_PASSWORD_MSG, CS_INCORRECT_PASSWORD_MSG

💼 Use Cases

Docker deployment with branding:

docker run -e CS_LOGIN_TITLE="ACME Corp Portal" \
           -e CS_LOGIN_ENV_PASSWORD_MSG="Contact IT for access" \
           -e CS_PASSWORD_PLACEHOLDER="Corporate ID" \
           codercom/code-server:latest

Corporate error messages:

code-server --missing-password-msg="Please enter your employee ID" \
           --incorrect-password-msg="Invalid credentials. Contact support."

🔧 Implementation Details

Priority order: CLI args → env vars → config file → i18n defaults
HTML escaping: All custom messages are automatically escaped for security
Internationalization: Non-customized messages still use locale files
Config file support: All options work in YAML config files
Testing: Comprehensive unit and integration tests added

🧪 Test Plan

CLI argument parsing for all new options
Environment variable processing
Config file YAML support
HTML output correctness (titles, placeholders, buttons)
HTML escaping security (XSS prevention)
Error message customization
Backwards compatibility with existing options
Internationalization preservation
Priority order (CLI > env > config > defaults)

📚 Documentation

Updated docs/install.md with Docker customization examples
Enhanced docs/FAQ.md with login customization section
Added comprehensive docs/customization.md guide
Updated main docs/README.md with link to customization guide

This enables powerful branding and customization for enterprise deployments while maintaining full backwards compatibility.

Add CLI arguments and environment variables to customize all login page elements: - Login title, subtitle, and welcome text - Password field placeholder and submit button text - Password instruction messages (config file, env var, hashed) - Error messages (rate limit, missing/incorrect password) New CLI options: --login-title, --login-below, --password-placeholder, --submit-text --login-password-msg, --login-env-password-msg, --login-hashed-password-msg --login-rate-limit-msg, --missing-password-msg, --incorrect-password-msg New environment variables: CS_LOGIN_TITLE, CS_LOGIN_BELOW, CS_PASSWORD_PLACEHOLDER, CS_SUBMIT_TEXT CS_LOGIN_PASSWORD_MSG, CS_LOGIN_ENV_PASSWORD_MSG, CS_LOGIN_HASHED_PASSWORD_MSG CS_LOGIN_RATE_LIMIT_MSG, CS_MISSING_PASSWORD_MSG, CS_INCORRECT_PASSWORD_MSG Features: - Full backwards compatibility with existing --app-name/--welcome-text - HTML escaping for security (prevents XSS) - Config file support (YAML) - Priority: CLI args > env vars > config file > defaults - Internationalization preserved for non-customized messages Perfect for Docker deployments and corporate branding. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <[email protected]>

code-asher · 2025-06-13T21:33:33Z

Thank you for the contribution!

Thinking out loud, my first impression is that the flags are not scaling well. Since we have this concept of language files that we can use for strings in the app, I wonder if we can re-use this for user-provided strings as well? Maybe we have a flag that accepts a json file (or accepts raw json itself) and then we can pass that to the i18n library (merged with the default language file).

Then, all strings, including future ones, will automatically be available for configuration. What do you think?

We could then also deprecate --welcome-msg and --app-name.

strickvl · 2025-06-13T21:43:46Z

Sounds good. I'll work on that change.

Replace non-scalable individual flags (--login-title, --login-below, etc.) with a unified --custom-strings flag that accepts JSON file paths or inline JSON for UI customization. This leverages the existing i18n system for better scalability and maintainability. Changes: - Add --custom-strings flag with JSON validation - Extend i18n system to merge custom strings with defaults - Remove newly-added individual login/UI flags - Deprecate legacy --app-name and --welcome-text flags - Update login route to use unified i18n system - Add comprehensive tests for new functionality - Update documentation with migration guide and examples 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <[email protected]>

Remove migration examples for flags that were never released. Only --app-name and --welcome-text were in the original codebase and might be used by existing users. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <[email protected]>

Replace outdated CS_* environment variable examples with the new --custom-strings flag approach. Include both inline JSON and mounted file examples for Docker users. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <[email protected]>

strickvl · 2025-06-21T13:11:58Z

@code-asher is this in line with what you were thinking?

code-asher

Yes this is exactly along the line I was thinking! Thank you, this is really great.

code-asher · 2025-06-23T21:59:44Z

docs/FAQ.md

+### Login page customization
+
+You can customize the login page using the `--custom-strings` flag:
+
+```bash
+code-server --custom-strings '{"LOGIN_TITLE": "My Code Server", "WELCOME": "Welcome to my portal"}'
+```
+
+Or use a JSON file:
+```bash
+code-server --custom-strings /path/to/custom-strings.json
+```
+
+Legacy individual flags (`--app-name`, `--welcome-text`) are still supported but deprecated.
+
+For detailed customization options and examples, see the [customization guide](./customization.md).
+


IMO this flag is too niche to earn a callout in the FAQ, so we should delete this.

code-asher · 2025-06-23T22:01:31Z

docs/README.md

+You can also customize the login page appearance - see our [customization guide](./customization.md).
+


I am thinking we append an entry to guide.md instead of the main readme. Something like:

## Internationalization and customization You can customize some of code-server's strings for either internationalization or customization purposes. See our [customization guide](./customization.md).

code-asher · 2025-06-23T22:12:02Z

docs/customization.md

@@ -0,0 +1,170 @@
+# Login Page Customization


What do you think about making this more generic rather than login-specific? I also think there is a fair bit of repetition here we could consolidate and I worry that this will get out of sync with the language file. We can also keep the legacy flags around, no need to say we might remove them eventually.

I also think it would be reasonable to keep this text in guide.md rather than linking out to a new file. We have so many markdown files sometimes I get lost. 😅

Maybe something like:

Internationalization and customization

code-server allows you to provide a language file or JSON to configure certain strings. This can be used for both internationalization and customization.

For example:

code-server --i18n /custom-strings.json code-server --i18n `{"WELCOME": "{{app}} ログイン"}`

Or this can be done in the config file:

i18n: | { "WELCOME": "Welcome to the {{app}} Development Portal", }

You can combine this with the --locale flag to configure language support for both code-server and VS Code in cases where code-server has no support but VS Code does. If you are using this for internationalization, please consider sending us a pull request to contribute it to i18n/locales.

Available keys and placeholders

Refer to ../src/node/i18n/locales/en.json for a full list of the available keys for translations. Note that the only placeholders supported for each key are the ones used in the default string.

The --app-name flag controls the {{app}} placeholder in templates. If you want to change the name, you can either:

Set --app-name (potentially alongside --i18n)

Use --i18n and hardcode the name in your strings

Legacy flag

The --welcome-text flag is now deprecated. Use the WELCOME key instead.

code-asher · 2025-06-23T22:30:03Z

docs/install.md

@@ -287,6 +287,34 @@ docker run -it --name code-server -p 127.0.0.1:8080:8080 \
  codercom/code-server:latest
 ```

+### Customizing the login page


This guide is just for installing code-server, I think we should omit this. Also the customization can be applied to any install method, not just Docker, so we would want to generalize it anyway.

code-asher · 2025-06-23T22:30:19Z

src/node/cli.ts

@@ -93,6 +93,7 @@ export interface UserProvidedArgs extends UserProvidedCodeArgs {
  "app-name"?: string
  "welcome-text"?: string
  "abs-proxy-base-path"?: string
+  "custom-strings"?: string


What do you think about calling it i18n?

code-asher · 2025-06-23T22:55:31Z

src/node/i18n/index.ts

+export async function loadCustomStrings(customStringsArg?: string): Promise<void> {
+  if (!customStringsArg) {
+    return
+  }


We already check the arg before passing it in, so we can make this non-optional.

Suggested change

export async function loadCustomStrings(customStringsArg?: string): Promise<void> {

if (!customStringsArg) {

return

}

export async function loadCustomStrings(customStringsArg: string): Promise<void> {

code-asher · 2025-06-23T23:01:16Z

src/node/main.ts

+  if (args["custom-strings"]) {
+    try {
+      await loadCustomStrings(args["custom-strings"])
+      logger.info("Loaded custom strings")
+    } catch (error) {
+      logger.error("Failed to load custom strings", field("error", error))
+      throw error
+    }
+  }


We already add Failed to load custom strings to the error, and any errors thrown here will already be logged (I think?), so I am thinking we remove the catch to avoid logging the error twice.

Suggested change

if (args["custom-strings"]) {

try {

await loadCustomStrings(args["custom-strings"])

logger.info("Loaded custom strings")

} catch (error) {

logger.error("Failed to load custom strings", field("error", error))

throw error

}

}

if (args["custom-strings"]) {

await loadCustomStrings(args["custom-strings"])

logger.info("Loaded custom strings")

}

code-asher · 2025-06-23T23:04:29Z

test/unit/node/cli.test.ts

+    delete process.env.CS_LOGIN_TITLE
+    delete process.env.CS_LOGIN_ENV_PASSWORD_MSG
+    delete process.env.CS_PASSWORD_PLACEHOLDER
+    delete process.env.CS_SUBMIT_TEXT


These env vars do not exist anymore, do they?

code-asher · 2025-06-23T23:42:17Z

src/node/i18n/index.ts

+
+    // Try to parse as JSON first
+    try {
+      customStringsData = JSON.parse(customStringsArg)


This automatic JSON/filename handling is really convenient but I worry about overloading the flag like this, especially with error handling since we might return a "file not found" error but really the user just mistyped their JSON and forgot the leading {, as one example.

I am not familiar with any precedent we can draw on for inspiration, but I have a few ideas:

We make --i18n take a file always, with no way to provide raw JSON (for now).

We make separate --i18n and --i18n-json flags.

We make --i18n take a file always, and use an environment variable if you want to pass raw JSON.

We make --i18n take a file always, and a new repeatable i18n-var flag. Usage would be code-server i18n-var "WELCOME=my welcome text" i18n-var "LOGIN_TITLE=my title". Something like that. This is kinda nice because there is no need to write JSON on the command line, but it feels a bit clunky.

Thoughts? I think maybe we skip the raw JSON input for now and figure it out later if folks ask for it, unless you feel strongly about including it!

code-asher · 2025-06-23T23:42:44Z

test/unit/node/routes/login.test.ts

@@ -146,5 +146,70 @@ describe("login", () => {
      expect(resp.status).toBe(200)
      expect(htmlContent).toContain(`欢迎来到 code-server`)
    })
+
+    it("should return custom login title", async () => {


Looks like these tests are outdated.

strickvl requested a review from a team as a code owner June 12, 2025 17:19

strickvl and others added 5 commits June 17, 2025 12:53

Merge branch 'main' into main

bac8b42

Merge branch 'main' into main

cacf3cc

strickvl closed this Jun 21, 2025

strickvl reopened this Jun 21, 2025

code-asher reviewed Jun 23, 2025

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Add comprehensive login page customization options #7374

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		You can also customize the login page appearance - see our [customization guide](./customization.md).

Add comprehensive login page customization options #7374

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strickvl commented Jun 12, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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🎯 Key Features

📋 New CLI Options

🐳 Environment Variables

💼 Use Cases

🔧 Implementation Details

🧪 Test Plan

📚 Documentation

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code-asher Jun 23, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Internationalization and customization

Available keys and placeholders

Legacy flag

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