mcp-ts-template
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A production-grade TypeScript template for building robust Model Context Protocol (MCP) servers, featuring built-in observability with OpenTelemetry, advanced error handling, comprehensive utilities, and a modular architecture.
220 lines • 10.3 kB
JavaScript
/**
* @fileoverview Provides a utility class `IdGenerator` for creating customizable, prefixed unique identifiers,
* and a standalone `generateUUID` function for generating standard UUIDs.
* The `IdGenerator` supports entity-specific prefixes, custom character sets, and lengths.
*
* Note: Logging has been removed from this module to prevent circular dependencies
* with the `requestContextService`, which itself uses `generateUUID` from this module.
* This was causing `ReferenceError: Cannot access 'generateUUID' before initialization`
* during application startup.
* @module src/utils/security/idGenerator
*/
import { randomUUID as cryptoRandomUUID, randomBytes } from "crypto";
import { BaseErrorCode, McpError } from "../../types-global/errors.js";
/**
* A generic ID Generator class for creating and managing unique, prefixed identifiers.
* Allows defining custom prefixes, generating random strings, and validating/normalizing IDs.
*/
export class IdGenerator {
/**
* Default character set for the random part of the ID.
* @private
*/
static DEFAULT_CHARSET = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
/**
* Default separator character between prefix and random part.
* @private
*/
static DEFAULT_SEPARATOR = "_";
/**
* Default length for the random part of the ID.
* @private
*/
static DEFAULT_LENGTH = 6;
/**
* Stores the mapping of entity types to their prefixes.
* @private
*/
entityPrefixes = {};
/**
* Stores a reverse mapping from prefixes (case-insensitive) to entity types.
* @private
*/
prefixToEntityType = {};
/**
* Constructs an `IdGenerator` instance.
* @param entityPrefixes - An initial map of entity types to their prefixes.
*/
constructor(entityPrefixes = {}) {
// Logging removed to prevent circular dependency with requestContextService.
this.setEntityPrefixes(entityPrefixes);
}
/**
* Sets or updates the entity prefix configuration and rebuilds the internal reverse lookup map.
* @param entityPrefixes - A map where keys are entity type names and values are their desired ID prefixes.
*/
setEntityPrefixes(entityPrefixes) {
// Logging removed.
this.entityPrefixes = { ...entityPrefixes };
this.prefixToEntityType = Object.entries(this.entityPrefixes).reduce((acc, [type, prefix]) => {
acc[prefix.toLowerCase()] = type; // Store lowercase for case-insensitive lookup
return acc;
}, {});
}
/**
* Retrieves a copy of the current entity prefix configuration.
* @returns The current entity prefix configuration.
*/
getEntityPrefixes() {
return { ...this.entityPrefixes };
}
/**
* Generates a cryptographically secure random string.
* @param length - The desired length of the random string. Defaults to `IdGenerator.DEFAULT_LENGTH`.
* @param charset - The character set to use. Defaults to `IdGenerator.DEFAULT_CHARSET`.
* @returns The generated random string.
*/
generateRandomString(length = IdGenerator.DEFAULT_LENGTH, charset = IdGenerator.DEFAULT_CHARSET) {
let result = "";
// Determine the largest multiple of charset.length that is less than or equal to 256
// This is the threshold for rejection sampling to avoid bias.
const maxValidByteValue = Math.floor(256 / charset.length) * charset.length;
while (result.length < length) {
const byteBuffer = randomBytes(1); // Get one random byte
const byte = byteBuffer[0];
// If the byte is within the valid range (i.e., it won't introduce bias),
// use it to select a character from the charset. Otherwise, discard and try again.
if (byte !== undefined && byte < maxValidByteValue) {
const charIndex = byte % charset.length;
const char = charset[charIndex];
if (char) {
result += char;
}
}
}
return result;
}
/**
* Generates a unique ID, optionally prepended with a prefix.
* @param prefix - An optional prefix for the ID.
* @param options - Optional parameters for ID generation (length, separator, charset).
* @returns A unique identifier string.
*/
generate(prefix, options = {}) {
// Logging removed.
const { length = IdGenerator.DEFAULT_LENGTH, separator = IdGenerator.DEFAULT_SEPARATOR, charset = IdGenerator.DEFAULT_CHARSET, } = options;
const randomPart = this.generateRandomString(length, charset);
const generatedId = prefix
? `${prefix}${separator}${randomPart}`
: randomPart;
return generatedId;
}
/**
* Generates a unique ID for a specified entity type, using its configured prefix.
* @param entityType - The type of entity (must be registered).
* @param options - Optional parameters for ID generation.
* @returns A unique identifier string for the entity (e.g., "PROJ_A6B3J0").
* @throws {McpError} If the `entityType` is not registered.
*/
generateForEntity(entityType, options = {}) {
const prefix = this.entityPrefixes[entityType];
if (!prefix) {
throw new McpError(BaseErrorCode.VALIDATION_ERROR, `Unknown entity type: ${entityType}. No prefix registered.`);
}
return this.generate(prefix, options);
}
/**
* Validates if an ID conforms to the expected format for a specific entity type.
* @param id - The ID string to validate.
* @param entityType - The expected entity type of the ID.
* @param options - Optional parameters used during generation for validation consistency.
* The `charset` from these options will be used for validation.
* @returns `true` if the ID is valid, `false` otherwise.
*/
isValid(id, entityType, options = {}) {
const prefix = this.entityPrefixes[entityType];
const { length = IdGenerator.DEFAULT_LENGTH, separator = IdGenerator.DEFAULT_SEPARATOR, charset = IdGenerator.DEFAULT_CHARSET, // Use charset from options or default
} = options;
if (!prefix) {
return false;
}
// Build regex character class from the charset
// Escape characters that have special meaning inside a regex character class `[]`
const escapedCharsetForClass = charset.replace(/[[\]\\^-]/g, "\\$&");
const charsetRegexPart = `[${escapedCharsetForClass}]`;
const pattern = new RegExp(`^${this.escapeRegex(prefix)}${this.escapeRegex(separator)}${charsetRegexPart}{${length}}$`);
return pattern.test(id);
}
/**
* Escapes special characters in a string for use in a regular expression.
* @param str - The string to escape.
* @returns The escaped string.
* @private
*/
escapeRegex(str) {
return str.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
}
/**
* Strips the prefix and separator from an ID string.
* @param id - The ID string (e.g., "PROJ_A6B3J0").
* @param separator - The separator used in the ID. Defaults to `IdGenerator.DEFAULT_SEPARATOR`.
* @returns The ID part without the prefix, or the original ID if separator not found.
*/
stripPrefix(id, separator = IdGenerator.DEFAULT_SEPARATOR) {
const parts = id.split(separator);
return parts.length > 1 ? parts.slice(1).join(separator) : id; // Handle separators in random part
}
/**
* Determines the entity type from an ID string by its prefix (case-insensitive).
* @param id - The ID string (e.g., "PROJ_A6B3J0").
* @param separator - The separator used in the ID. Defaults to `IdGenerator.DEFAULT_SEPARATOR`.
* @returns The determined entity type.
* @throws {McpError} If ID format is invalid or prefix is unknown.
*/
getEntityType(id, separator = IdGenerator.DEFAULT_SEPARATOR) {
const parts = id.split(separator);
if (parts.length < 2 || !parts[0]) {
throw new McpError(BaseErrorCode.VALIDATION_ERROR, `Invalid ID format: ${id}. Expected format like: PREFIX${separator}RANDOMLPART`);
}
const prefix = parts[0];
const entityType = this.prefixToEntityType[prefix.toLowerCase()];
if (!entityType) {
throw new McpError(BaseErrorCode.VALIDATION_ERROR, `Unknown entity type for prefix: ${prefix}`);
}
return entityType;
}
/**
* Normalizes an entity ID to ensure the prefix matches the registered case
* and the random part is uppercase. Note: This assumes the charset characters
* have a meaningful uppercase version if case-insensitivity is desired for the random part.
* For default charset (A-Z0-9), this is fine. For custom charsets, behavior might vary.
* @param id - The ID to normalize (e.g., "proj_a6b3j0").
* @param separator - The separator used in the ID. Defaults to `IdGenerator.DEFAULT_SEPARATOR`.
* @returns The normalized ID (e.g., "PROJ_A6B3J0").
* @throws {McpError} If the entity type cannot be determined from the ID.
*/
normalize(id, separator = IdGenerator.DEFAULT_SEPARATOR) {
const entityType = this.getEntityType(id, separator);
const registeredPrefix = this.entityPrefixes[entityType];
const idParts = id.split(separator);
const randomPart = idParts.slice(1).join(separator);
// Consider if randomPart.toUpperCase() is always correct for custom charsets.
// For now, maintaining existing behavior.
return `${registeredPrefix}${separator}${randomPart.toUpperCase()}`;
}
}
/**
* Default singleton instance of the `IdGenerator`.
* Initialize with `idGenerator.setEntityPrefixes({})` to configure.
*/
export const idGenerator = new IdGenerator();
/**
* Generates a standard Version 4 UUID (Universally Unique Identifier).
* Uses the Node.js `crypto` module. This function is independent of the IdGenerator instance
* to prevent circular dependencies when used by other utilities like requestContextService.
* @returns A new UUID string.
*/
export const generateUUID = () => {
return cryptoRandomUUID();
};
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