Parse additional fields from error and notice response messages

Author: malthe

CHANGES.md

@@ -1,6 +1,11 @@
 In next release ...
 
--
+- The PostgreSQL error code table has been removed. Consult the documentation to
+  map error codes to the string identifiers used in the PostgreSQL codebase. 
+
+- Parse additional fields into `DatabaseError` and `ClientNotice`. Note that a
+  `detail` field has been added (previously it was added to the message) as
+  part of this change.
 
 ## v2.0.0 (2024-02-29)
 

src/client.ts

@@ -15,7 +15,6 @@ import { EventEmitter } from 'node:events';
 import { Defaults } from './defaults.js';
 import * as logger from './logging.js';
 
-import { postgresqlErrorCodes } from './errors.js';
 import { Queue } from './queue.js';
 import { Query } from './query.js';
 
@@ -30,7 +29,6 @@ import {
     ClientConnectionDefaults,
     ClientConnectionOptions,
     DatabaseError,
-    ErrorLevel,
     Message,
     Reader,
     RowDescription,
@@ -52,11 +50,7 @@ export interface ConnectionInfo {
     parameters: ReadonlyMap<string, string>;
 }
 
-export interface ClientNotice extends DatabaseError {
-    level: ErrorLevel;
-    code: keyof typeof postgresqlErrorCodes;
-    message: string;
-}
+export interface ClientNotice extends DatabaseError {}
 
 export interface DataTypeError {
     dataType: DataType;
@@ -780,11 +774,7 @@ export class ClientImpl {
     }
 
     private parseError(buffer: Buffer) {
-        let level: DatabaseError['level'] | null = null;
-        let code: DatabaseError['code'] | null = null;
-        let message: DatabaseError['message'] | null = null;
-        let details: string | null = null;
-
+        const params: Partial<ConstructorParameters<typeof DatabaseError>> = [];
         const length = buffer.length;
         let offset = 0;
 
@@ -793,45 +783,74 @@ export class ClientImpl {
             if (next < 0) break;
 
             const value = buffer.subarray(offset + 1, next).toString();
-            switch (buffer[offset]) {
+
+            // See https://www.postgresql.org/docs/current/protocol-error-fields.html
+            const token = buffer[offset];
+            switch (token) {
+                // S:
                 case 0x53: {
-                    if (level === null) {
-                        level = value as DatabaseError['level'];
-                    }
+                    params[0] = value as DatabaseError['level'];
                     break;
                 }
+                // V:
+                // This is present only in messages generated by PostgreSQL
+                // versions 9.6 and later, taking priority over the previous
+                // case.
                 case 0x56: {
-                    level = value as DatabaseError['level'];
+                    params[0] = value as DatabaseError['level'];
                     break;
                 }
+                // C:
                 case 0x43: {
-                    code = value as DatabaseError['code'];
+                    params[1] = value as DatabaseError['code'];
                     break;
                 }
+                // M:
+                case 0x4d: {
+                    params[2] = value;
+                    break;
+                }
+                // D:
                 case 0x44: {
-                    details = value;
+                    params[3] = value;
                     break;
                 }
-                case 0x4d: {
-                    message = value;
+                // F:
+                case 0x46: {
+                    params[4] = value;
                     break;
                 }
-                default:
+                // H:
+                case 0x48: {
+                    params[5] = value;
                     break;
+                }
+                // L:
+                case 0x4c: {
+                    params[6] = parseInt(value);
+                    break;
+                }
+                // P:
+                case 0x50: {
+                    params[7] = value;
+                    break;
+                }
+                // R:
+                case 0x52: {
+                    params[8] = parseInt(value);
+                    break;
+                }
             }
 
             offset = next + 1;
         }
 
+        const [level, code, message, ...optional] = params;
         if (level && code && message) {
-            return new DatabaseError(
-                level,
-                code,
-                details ? `${message}: ${details}` : message,
-            );
+            return new DatabaseError(level, code, message, ...optional);
         }
 
-        throw new Error('Unable to parse error message.');
+        throw new Error('Malformed error response');
     }
 
     private handle(buffer: Buffer, offset: number, size: number): number {