Implementation:Langgenius Dify Error Parser

Knowledge Sources	Langgenius_Dify
Domains	Frontend, Utilities
Last Updated	2026-02-12 07:00 GMT

Overview

Extracts human-readable error messages from nested plugin invocation error structures.

Description

This utility provides the parsePluginErrorMessage function, which handles the common pattern where Dify plugin errors are wrapped inside a PluginInvokeError JSON string embedded within a larger error message. The function accepts either a Response object (from fetch/ky) or a standard error object, extracts the raw message, then applies a regex to locate and parse the embedded JSON payload. It returns the innermost message field when available, falls back to error_type, and ultimately returns the raw message if no nested structure is found. This ensures users see meaningful, actionable error messages rather than raw JSON or request IDs.

Usage

Use parsePluginErrorMessage in error handling paths for plugin-related API calls, particularly when the backend returns errors in the format req_id: xxx PluginInvokeError: {"message":"..."}. This is typically called in catch blocks or error response handlers.

Code Reference

Source Location

Repository: Langgenius_Dify
File: web/utils/error-parser.ts
Lines: 1-52

Signature

export const parsePluginErrorMessage = async (error: any): Promise<string>

Import

import { parsePluginErrorMessage } from '@/utils/error-parser'

I/O Contract

Inputs

Name	Type	Required	Description
error	`any`	Yes	An error object; can be a fetch `Response` object, a standard `Error`, or any object with a `message` property

Outputs

Name	Type	Description
(return value)	`Promise<string>`	The extracted human-readable error message; defaults to "Unknown error" if nothing can be parsed

Usage Examples

Parse a Plugin Invoke Error from a Response

import { parsePluginErrorMessage } from '@/utils/error-parser'

try {
  const response = await fetch('/api/plugin/invoke', { method: 'POST', body: payload })
  if (!response.ok) {
    const message = await parsePluginErrorMessage(response)
    // message: "Bad credentials" (extracted from nested JSON)
    showError(message)
  }
} catch (err) {
  const message = await parsePluginErrorMessage(err)
  showError(message)
}

Parse a Standard Error Object

import { parsePluginErrorMessage } from '@/utils/error-parser'

const error = new Error('req_id: abc123 PluginInvokeError: {"message":"API rate limit exceeded","error_type":"RateLimitError"}')
const message = await parsePluginErrorMessage(error)
// message: "API rate limit exceeded"

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