feat(ruby): Add API key (header-based) authentication support to Ruby SDK generator (#9882)

* Add API key (header-based) authentication support to Ruby SDK generator

- Implement header authentication scheme in RootClientGenerator
- Add constructor parameter for header auth schemes with environment variable support
- Add header auth scheme to raw client headers with optional prefix support
- Successfully tested with custom-auth fixture (X-API-KEY header)
- Follows same pattern as Python generator implementation

Co-Authored-By: Deep Singhvi <[email protected]>

* Fix: Use header wire value for parameter naming instead of scheme name

- Changed parameter name from scheme name to snake_case of header wire value
- Example: X-API-KEY header now generates x_api_key parameter instead of custom_auth_scheme
- Imported snakeCase from lodash-es for string conversion
- Updated both parameter creation and header value references to use consistent naming

Co-Authored-By: Deep Singhvi <[email protected]>

* Use Fern name field for header parameter naming

- Removed manual lodash snakeCase conversion
- Using header.name.name.snakeCase.safeName instead of snakeCase(header.name.wireValue)
- This ensures proper use of Fern's built-in name conversion

Co-Authored-By: Deep Singhvi <[email protected]>

* Add any-auth fixture support for API key authentication

- Generated output now includes X-API-Key header alongside Bearer token
- Test passes successfully with ruby-sdk-v2 generator

Co-Authored-By: Deep Singhvi <[email protected]>

* Fix: Support multiple authentication parameters in client constructor

- Changed getAuthenticationParameter() to getAuthenticationParameters() returning an array
- Now handles APIs with multiple auth schemes (e.g., any-auth with bearer + API key)
- Fixes missing api_key parameter issue in any-auth fixture
- Both token and api_key are now properly added to constructor with ENV defaults

Co-Authored-By: Deep Singhvi <[email protected]>

* chore: Add changelog entry for v1.0.0-rc29

- Added API key (header-based) authentication support
- Added support for multiple authentication schemes in the same API

Co-Authored-By: Deep Singhvi <[email protected]>

---------

Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Co-authored-by: Deep Singhvi <[email protected]>
Co-authored-by: Piper Gragg <[email protected]>

Author: 3 people

generators/ruby-v2/sdk/src/root-client/RootClientGenerator.ts

@@ -56,10 +56,8 @@ export class RootClientGenerator extends FileGenerator<RubyFile, SdkCustomConfig
         });
         parameters.push(baseUrlParameter);
 
-        const authenticationParameter = this.getAuthenticationParameter();
-        if (authenticationParameter != null) {
-            parameters.push(authenticationParameter);
-        }
+        const authenticationParameters = this.getAuthenticationParameters();
+        parameters.push(...authenticationParameters);
 
         const method = ruby.method({
             name: "initialize",
@@ -92,11 +90,13 @@ export class RootClientGenerator extends FileGenerator<RubyFile, SdkCustomConfig
         return method;
     }
 
-    private getAuthenticationParameter(): ruby.KeywordParameter | undefined {
+    private getAuthenticationParameters(): ruby.KeywordParameter[] {
+        const parameters: ruby.KeywordParameter[] = [];
+
         for (const scheme of this.context.ir.auth.schemes) {
             switch (scheme.type) {
-                case "bearer":
-                    return ruby.parameters.keyword({
+                case "bearer": {
+                    const param = ruby.parameters.keyword({
                         name: TOKEN_PARAMETER_NAME,
                         type: ruby.Type.string(),
                         initializer:
@@ -107,12 +107,30 @@ export class RootClientGenerator extends FileGenerator<RubyFile, SdkCustomConfig
                                 : undefined,
                         docs: undefined
                     });
+                    parameters.push(param);
+                    break;
+                }
+                case "header": {
+                    const param = ruby.parameters.keyword({
+                        name: scheme.name.name.snakeCase.safeName,
+                        type: ruby.Type.string(),
+                        initializer:
+                            scheme.headerEnvVar != null
+                                ? ruby.codeblock((writer) => {
+                                      writer.write(`ENV.fetch("${scheme.headerEnvVar}", nil)`);
+                                  })
+                                : undefined,
+                        docs: undefined
+                    });
+                    parameters.push(param);
+                    break;
+                }
                 default:
-                    return undefined;
+                    break;
             }
         }
 
-        return undefined;
+        return parameters;
     }
 
     private getRawClientHeaders(): ruby.TypeLiteral {
@@ -138,6 +156,17 @@ export class RootClientGenerator extends FileGenerator<RubyFile, SdkCustomConfig
                         value: ruby.TypeLiteral.string(`Bearer #{${TOKEN_PARAMETER_NAME}}`)
                     });
                     break;
+                case "header": {
+                    const headerParamName = header.name.name.snakeCase.safeName;
+                    const headerName = header.name.wireValue;
+                    const headerValue =
+                        header.prefix != null ? `${header.prefix} #{${headerParamName}}` : `#{${headerParamName}}`;
+                    headers.push({
+                        key: ruby.TypeLiteral.string(headerName),
+                        value: ruby.TypeLiteral.string(headerValue)
+                    });
+                    break;
+                }
                 default:
                     break;
             }

generators/ruby-v2/sdk/versions.yml

@@ -1,5 +1,14 @@
 # yaml-language-server: $schema=../../../fern-versions-yml.schema.json
 
+- version: 1.0.0-rc29
+  createdAt: "2025-10-21"
+  changelogEntry:
+    - type: feat
+      summary: |
+        Add support for API key (header-based) authentication in Ruby SDK generator.
+        Supports multiple authentication schemes in the same API.
+  irVersion: 59
+
 - version: 1.0.0-rc28
   createdAt: "2025-10-01"
   changelogEntry: