refactor: allow service-specific API errors to be registered

src/backend/src/api/APIError.js

@@ -324,36 +324,6 @@ module.exports = class APIError {
             message: () => 'Invalid token.',
         },
 
-        // drivers
-        'interface_not_found': {
-            status: 404,
-            message: ({ interface_name }) => `Interface not found: ${quot(interface_name)}`,
-        },
-        'no_implementation_available': {
-            status: 502,
-            message: ({
-                iface,
-                interface_name,
-                driver
-            }) => `No implementation available for ` +
-                (iface ?? interface_name) ? 'interface' : 'driver' +
-                ' ' + quot(iface ?? interface_name ?? driver) + '.',
-        },
-        'method_not_found': {
-            status: 404,
-            message: ({ interface_name, method_name }) => `Method not found: ${quot(method_name)} on interface ${quot(interface_name)}`,
-        },
-        'missing_required_argument': {
-            status: 400,
-            message: ({ interface_name, method_name, arg_name }) =>
-                `Missing required argument ${quot(arg_name)} for method ${quot(method_name)} on interface ${quot(interface_name)}`,
-        },
-        'argument_consolidation_failed': {
-            status: 400,
-            message: ({ interface_name, method_name, arg_name, message }) =>
-                `Failed to parse or process argument ${quot(arg_name)} for method ${quot(method_name)} on interface ${quot(interface_name)}: ${message}`,
-        },
-
         // SLA
         'rate_limit_exceeded': {
             status: 429,

src/backend/src/modules/web/APIErrorService.js

@@ -0,0 +1,54 @@
+const APIError = require("../../api/APIError");
+const BaseService = require("../../services/BaseService");
+
+/**
+ * @typedef {Object} ErrorSpec
+ * @property {string} code - The error code
+ * @property {string} status - HTTP status code
+ * @property {function} message - A function that generates an error message
+ */
+
+/**
+ * The APIErrorService class provides a mechanism for registering and managing
+ * error codes and messages which may be sent to clients.
+ * 
+ * This allows for a single source-of-truth for error codes and messages that
+ * are used by multiple services.
+ */
+class APIErrorService extends BaseService {
+    _construct () {
+        this.codes = {
+            ...this.constructor.codes,
+        };
+    }
+
+    // Hardcoded error codes from before this service was created
+    static codes = APIError.codes;
+    
+    /**
+     * Registers API error codes.
+     * 
+     * @param {Object.<string, ErrorSpec>} codes - A map of error codes to error specifications
+     */
+    register (codes) {
+        for ( const code in codes ) {
+            this.codes[code] = codes[code];
+        }
+    }
+    
+    create (code, fields) {
+        const error_spec = this.codes[code];
+        if ( ! error_spec ) {
+            return new APIError(500, 'Missing error message.', null, {
+                code,
+            });
+        }
+        
+        return new APIError(error_spec.status, error_spec.message, null, {
+            ...fields,
+            code,
+        });
+    }
+}
+
+module.exports = APIErrorService;

src/backend/src/modules/web/WebModule.js

@@ -19,6 +19,9 @@ class WebModule extends AdvancedBase {
         
         const WebServerService = require("./WebServerService");
         services.registerService('web-server', WebServerService);
+        
+        const APIErrorService = require("./APIErrorService");
+        services.registerService('api-error', APIErrorService);
     }
 }
 

src/backend/src/services/drivers/DriverService.js

@@ -26,6 +26,8 @@ const { PermissionUtil } = require("../auth/PermissionService");
 const { Invoker } = require("../../../../putility/src/libs/invoker");
 const { get_user } = require("../../helpers");
 
+const strutil = require('@heyputer/putility').libs.string;
+
 /**
  * DriverService provides the functionality of Puter drivers.
  * This class is responsible for managing and interacting with Puter drivers.
@@ -51,6 +53,50 @@ class DriverService extends BaseService {
         this.service_aliases = {};
     }
 
+    /**
+    * This method is responsible for calling a driver's method with provided arguments.
+    * It checks for permissions, selects the best option, and applies rate and monthly usage limits before invoking the driver.
+    *
+    * @param {Object} o - An object containing driver, interface, method, and arguments.
+    * @returns {Promise<{success: boolean, service: DriverService.Driver, result: any, metadata: any}>}
+    */
+    _init () {
+        const svc_registry = this.services.get('registry');
+        svc_registry.register_collection('');
+        
+        const { quot } = strutil;
+        const svc_apiError = this.services.get('api-error');
+        svc_apiError.register({
+            'missing_required_argument': {
+                status: 400,
+                message: ({ interface_name, method_name, arg_name }) =>
+                    `Missing required argument ${quot(arg_name)} for method ${quot(method_name)} on interface ${quot(interface_name)}`,
+            },
+            'argument_consolidation_failed': {
+                status: 400,
+                message: ({ interface_name, method_name, arg_name, message }) =>
+                    `Failed to parse or process argument ${quot(arg_name)} for method ${quot(method_name)} on interface ${quot(interface_name)}: ${message}`,
+            },
+            'interface_not_found': {
+                status: 404,
+                message: ({ interface_name }) => `Interface not found: ${quot(interface_name)}`,
+            },
+            'method_not_found': {
+                status: 404,
+                message: ({ interface_name, method_name }) => `Method not found: ${quot(method_name)} on interface ${quot(interface_name)}`,
+            },
+            'no_implementation_available': {
+                status: 502,
+                message: ({
+                    iface,
+                    interface_name,
+                    driver
+                }) => `No implementation available for ` +
+                    (iface ?? interface_name) ? 'interface' : 'driver' +
+                    ' ' + quot(iface ?? interface_name ?? driver) + '.',
+            },
+        });
+    }
     
     /**
     * This method is responsible for registering collections in the service registry.
@@ -91,19 +137,6 @@ class DriverService extends BaseService {
             { col_drivers });
     }
     
-
-    /**
-    * This method is responsible for calling a driver's method with provided arguments.
-    * It checks for permissions, selects the best option, and applies rate and monthly usage limits before invoking the driver.
-    *
-    * @param {Object} o - An object containing driver, interface, method, and arguments.
-    * @returns {Promise<{success: boolean, service: DriverService.Driver, result: any, metadata: any}>}
-    */
-    _init () {
-        const svc_registry = this.services.get('registry');
-        svc_registry.register_collection('');
-    }
-
     register_driver (interface_name, implementation) {
         this.interface_to_implementation[interface_name] = implementation;
     }
@@ -235,7 +268,8 @@ class DriverService extends BaseService {
         })();
 
         if ( ! driver_service_exists ) {
-            throw APIError.create('no_implementation_available', null, { iface })
+            const svc_apiError = this.services.get('api-error');
+            throw svc_apiError.create('no_implementation_available', { iface });
         }
 
         const service = this.services.get(driver);
@@ -531,16 +565,18 @@ class DriverService extends BaseService {
         const c_interfaces = svc_registry.get('interfaces');
         const c_types = svc_registry.get('types');
         
+        const svc_apiError = this.services.get('api-error');
+
         // Note: 'interface' is a strict mode reserved word.
         const interface_ = c_interfaces.get(interface_name);
         if ( ! interface_ ) {
-            throw APIError.create('interface_not_found', null, { interface_name });
+            throw svc_apiError.create('interface_not_found', { interface_name });
         }
 
         const processed_args = {};
         const method = interface_.methods[method_name];
         if ( ! method ) {
-            throw APIError.create('method_not_found', null, { interface_name, method_name });
+            throw svc_apiError.create('method_not_found', { interface_name, method_name });
         }
         
         for ( const [arg_name, arg_descriptor] of Object.entries(method.parameters) ) {
@@ -551,7 +587,7 @@ class DriverService extends BaseService {
             // There's a particular way I want to do this that involves
             // a trait for extensible behaviour.
             if ( arg_value === undefined && arg_descriptor.required ) {
-                throw APIError.create('missing_required_argument', null, {
+                throw svc_apiError.create('missing_required_argument', {
                     interface_name,
                     method_name,
                     arg_name,
@@ -564,7 +600,7 @@ class DriverService extends BaseService {
                 processed_args[arg_name] = await arg_behaviour.consolidate(
                     ctx, arg_value, { arg_descriptor, arg_name });
             } catch ( e ) {
-                throw APIError.create('argument_consolidation_failed', null, {
+                throw svc_apiError.create('argument_consolidation_failed', {
                     interface_name,
                     method_name,
                     arg_name,