Add MySQL connection string support (Issue #35)

Implements support for MYSQL_CONNECTION_STRING environment variable as an alternative to individual connection parameters. This is particularly useful for rotating credentials that expire frequently.

Features:
- Parse MySQL CLI-format connection strings
- Connection string takes precedence over individual env vars
- Support for -h/-P/-u/-p flags and long-form options
- Handles quoted values and complex passwords
- Documented as optional alternative in README

Addresses #35

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: echarrod

.env.dist

@@ -6,6 +6,12 @@ MYSQL_USER=root
 MYSQL_PASS=your_password
 MYSQL_DB=
 
+# Alternative: MySQL connection string (mysql CLI format)
+# If provided, this takes precedence over individual connection settings above
+# Useful for rotating credentials or temporary connections
+# Example: mysql --default-auth=mysql_native_password -A -hHOST -PPORT -uUSER -pPASS database_name
+# MYSQL_CONNECTION_STRING=
+
 # Leave MYSQL_DB empty for multi-DB mode
 # Set MYSQL_DB to a specific database name for single-DB mode
 

README.md

@@ -502,6 +502,19 @@ For more control over the MCP server's behavior, you can use these advanced conf
 - `MYSQL_PASS`: MySQL password
 - `MYSQL_DB`: Target database name (leave empty for multi-DB mode)
 
+#### Alternative: Connection String
+
+For scenarios requiring frequent credential rotation or temporary connections, you can use a MySQL connection string instead of individual environment variables:
+
+- `MYSQL_CONNECTION_STRING`: MySQL CLI-format connection string (e.g., `mysql --default-auth=mysql_native_password -A -hHOST -PPORT -uUSER -pPASS database_name`)
+
+When `MYSQL_CONNECTION_STRING` is provided, it takes precedence over individual connection settings. This is particularly useful for:
+- Rotating credentials that expire frequently
+- Temporary database connections
+- Quick testing with different database configurations
+
+**Note:** For security, this should only be set via environment variables, not stored in version-controlled configuration files. Consider using the `prompt` input type in Claude Code's MCP configuration for credentials that expire.
+
 ### Performance Configuration
 
 - `MYSQL_POOL_SIZE`: Connection pool size (default: "10")

src/config/index.ts

@@ -1,12 +1,18 @@
 import * as dotenv from "dotenv";
 import { SchemaPermissions } from "../types/index.js";
-import { parseSchemaPermissions } from "../utils/index.js";
+import { parseSchemaPermissions, parseMySQLConnectionString } from "../utils/index.js";
 
 export const MCP_VERSION = "2.0.2";
 
 // @INFO: Load environment variables from .env file
 dotenv.config();
 
+// @INFO: Parse connection string if provided
+// Connection string takes precedence over individual environment variables
+const connectionStringConfig = process.env.MYSQL_CONNECTION_STRING
+  ? parseMySQLConnectionString(process.env.MYSQL_CONNECTION_STRING)
+  : {};
+
 // @INFO: Update the environment setup to ensure database is correctly set
 if (process.env.NODE_ENV === "test" && !process.env.MYSQL_DB) {
   process.env.MYSQL_DB = "mcp_test_db"; // @INFO: Ensure we have a database name for tests
@@ -42,8 +48,9 @@ export const REMOTE_SECRET_KEY = process.env.REMOTE_SECRET_KEY || "";
 export const PORT = process.env.PORT || 3000;
 
 // Check if we're in multi-DB mode (no specific DB set)
+const dbFromEnvOrConnString = connectionStringConfig.database || process.env.MYSQL_DB;
 export const isMultiDbMode =
-  !process.env.MYSQL_DB || process.env.MYSQL_DB.trim() === "";
+  !dbFromEnvOrConnString || dbFromEnvOrConnString.trim() === "";
 
 export const mcpConfig = {
   server: {
@@ -52,23 +59,33 @@ export const mcpConfig = {
     connectionTypes: ["stdio", "streamableHttp"],
   },
   mysql: {
-    // Use Unix socket if provided, otherwise use host/port
-    ...(process.env.MYSQL_SOCKET_PATH
+    // Use Unix socket if provided (connection string takes precedence), otherwise use host/port
+    ...(connectionStringConfig.socketPath || process.env.MYSQL_SOCKET_PATH
       ? {
-          socketPath: process.env.MYSQL_SOCKET_PATH,
+          socketPath: connectionStringConfig.socketPath || process.env.MYSQL_SOCKET_PATH,
         }
       : {
-          host: process.env.MYSQL_HOST || "127.0.0.1",
-          port: Number(process.env.MYSQL_PORT || "3306"),
+          host: connectionStringConfig.host || process.env.MYSQL_HOST || "127.0.0.1",
+          port: connectionStringConfig.port || Number(process.env.MYSQL_PORT || "3306"),
         }),
-    user: process.env.MYSQL_USER || "root",
+    user: connectionStringConfig.user || process.env.MYSQL_USER || "root",
     password:
-      process.env.MYSQL_PASS === undefined ? "" : process.env.MYSQL_PASS,
-    database: process.env.MYSQL_DB || undefined, // Allow undefined database for multi-DB mode
+      connectionStringConfig.password !== undefined
+        ? connectionStringConfig.password
+        : process.env.MYSQL_PASS === undefined
+          ? ""
+          : process.env.MYSQL_PASS,
+    database: connectionStringConfig.database || process.env.MYSQL_DB || undefined, // Allow undefined database for multi-DB mode
     connectionLimit: 10,
     authPlugins: {
       mysql_clear_password: () => () =>
-        Buffer.from(process.env.MYSQL_PASS || "root"),
+        Buffer.from(
+          connectionStringConfig.password !== undefined
+            ? connectionStringConfig.password
+            : process.env.MYSQL_PASS !== undefined
+              ? process.env.MYSQL_PASS
+              : ""
+        ),
     },
     ...(process.env.MYSQL_SSL === "true"
       ? {

src/utils/index.ts

@@ -42,3 +42,132 @@ export function parseSchemaPermissions(
 
   return permissions;
 }
+
+// MySQL connection configuration type
+export interface MySQLConnectionConfig {
+  host?: string;
+  port?: number;
+  user?: string;
+  password?: string;
+  database?: string;
+  socketPath?: string;
+}
+
+// Function to parse MySQL connection string (mysql CLI format)
+// Example: mysql --default-auth=mysql_native_password -A -hrdsproxy.staging.luno.com -P3306 -uUSER -pPASS database_name
+export function parseMySQLConnectionString(
+  connectionString: string,
+): MySQLConnectionConfig {
+  const config: MySQLConnectionConfig = {};
+
+  // Remove 'mysql' command at the start if present
+  let cleanedString = connectionString.trim().replace(/^mysql\s+/, '');
+
+  // Parse flags and options
+  const tokens = [];
+  let currentToken = '';
+  let inQuotes = false;
+  let quoteChar: string | null = null;
+
+  for (let i = 0; i < cleanedString.length; i++) {
+    const char = cleanedString[i];
+
+    if ((char === '"' || char === "'") && (!inQuotes || char === quoteChar)) {
+      // Toggle quote state without adding the quote character
+      inQuotes = !inQuotes;
+      quoteChar = inQuotes ? char : null;
+    } else if (char === ' ' && !inQuotes) {
+      if (currentToken) {
+        tokens.push(currentToken);
+        currentToken = '';
+      }
+    } else {
+      currentToken += char;
+    }
+  }
+
+  if (currentToken) {
+    tokens.push(currentToken);
+  }
+
+  // Process tokens
+  for (let i = 0; i < tokens.length; i++) {
+    const token = tokens[i];
+
+    // Check for combined short options (e.g., -uUSER, -pPASS, -hHOST, -PPORT)
+    if (token.startsWith('-') && !token.startsWith('--')) {
+      const flag = token[1];
+      let value = token.substring(2);
+
+      // If no value attached, check next token
+      if (!value && i + 1 < tokens.length && !tokens[i + 1].startsWith('-')) {
+        value = tokens[i + 1];
+        i++;
+      }
+
+      switch (flag) {
+        case 'h':
+          config.host = value;
+          break;
+        case 'P': {
+          const port = parseInt(value, 10);
+          if (Number.isNaN(port) || !Number.isFinite(port) || port < 1 || port > 65535) {
+            throw new Error(`Invalid port: ${value}`);
+          }
+          config.port = port;
+          break;
+        }
+        case 'u':
+          config.user = value;
+          break;
+        case 'p':
+          config.password = value;
+          break;
+        case 'S':
+          config.socketPath = value;
+          break;
+      }
+    }
+    // Check for long options (e.g., --host=HOST, --port=PORT)
+    else if (token.startsWith('--')) {
+      const [flag, ...valueParts] = token.substring(2).split('=');
+      let value = valueParts.join('=');
+
+      // If no value with =, check next token
+      if (!value && i + 1 < tokens.length && !tokens[i + 1].startsWith('-')) {
+        value = tokens[i + 1];
+        i++;
+      }
+
+      switch (flag) {
+        case 'host':
+          config.host = value;
+          break;
+        case 'port': {
+          const port = parseInt(value, 10);
+          if (Number.isNaN(port) || !Number.isFinite(port) || port < 1 || port > 65535) {
+            throw new Error(`Invalid port: ${value}`);
+          }
+          config.port = port;
+          break;
+        }
+        case 'user':
+          config.user = value;
+          break;
+        case 'password':
+          config.password = value;
+          break;
+        case 'socket':
+          config.socketPath = value;
+          break;
+      }
+    }
+    // Last positional argument (not starting with -) is the database name
+    else if (!token.startsWith('-')) {
+      // Only consider it a database if it's one of the last arguments and not part of a flag
+      config.database = token;
+    }
+  }
+
+  return config;
+}