Update Attachment in Knowledge Folder

Replace an existing file in a Knowledge base with a new version

PATCH /knowledge/{folderId}

Update a file in a knowledge folder

cURL

curl --request PATCH \
  --url https://api.langdock.com/knowledge/{folderId} \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: multipart/form-data' \
  --form file='@example-file' \
  --form 'url=<string>' \
  --form 'attachmentId=<string>'

400

{
  "message": "The file \"updated-report.pdf\" is declared as a PDF but its content does not start with the expected PDF header.",
  "code": "BAD_REQUEST"
}

Updates an existing file (attachment) in a Knowledge base by replacing it with a new version. The old file is removed and the new file is processed and embedded.

Before You Start

• API key scope: Requires an API key with the KNOWLEDGE_FOLDER_API scope. The API key itself needs the Editor role on the Knowledge base. See Share Knowledge bases with the API for setup instructions.
• Knowledge bases: The Knowledge Folder API manages resources that appear as Knowledge bases in the Library.

Base URL

https://api.langdock.com

Dedicated deployments

Replace api.langdock.com with <your-deployment-url>/api/public in all requests.

Request Format

This endpoint accepts multipart/form-data requests with the file attached.

Path Parameters

Parameter	Type	Required	Description
folderId	string	Yes	The ID of the Knowledge base

Form Fields

Field	Type	Required	Description
attachmentId	string	Yes	The ID of the attachment to update
file	file	Yes	The new file to upload. See size limits below.
url	string	No	URL shown to users when this file is used in an answer

File size limits depend on the file type: 10 MB for plain text, Markdown, JSON, and VTT files; 30 MB for XML files; and 256 MB for other supported document types. See the supported file types reference for supported formats.

Examples

Update with cURL

curl -X PATCH "https://api.langdock.com/knowledge/{folderId}" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -F "attachmentId=att_abc123def456" \
  -F "file=@/path/to/new-document.pdf"

Update with JavaScript

const FormData = require("form-data");
const fs = require("fs");
const axios = require("axios");

async function updateAttachment(folderId, attachmentId, filePath) {
  const form = new FormData();
  form.append("attachmentId", attachmentId);
  form.append("file", fs.createReadStream(filePath));

  const response = await axios.patch(
    `https://api.langdock.com/knowledge/${folderId}`,
    form,
    {
      headers: {
        Authorization: "Bearer YOUR_API_KEY",
        ...form.getHeaders(),
      },
    }
  );

  return response.data;
}

// Example usage
try {
  const result = await updateAttachment(
    "folder_abc123",
    "att_xyz789",
    "/path/to/updated-report.pdf"
  );
  console.log("Attachment updated:", result);
} catch (error) {
  console.error("Failed to update:", error.response?.data?.message);
}

Update with Source URL

const FormData = require("form-data");
const fs = require("fs");
const axios = require("axios");

async function updateAttachmentWithUrl(folderId, attachmentId, filePath, sourceUrl) {
  const form = new FormData();
  form.append("attachmentId", attachmentId);
  form.append("file", fs.createReadStream(filePath));
  form.append("url", sourceUrl);

  const response = await axios.patch(
    `https://api.langdock.com/knowledge/${folderId}`,
    form,
    {
      headers: {
        Authorization: "Bearer YOUR_API_KEY",
        ...form.getHeaders(),
      },
    }
  );

  return response.data;
}

Response Format

Success Response (200 OK)

{
  status: "success";
  result: {
    id: string;          // Unique attachment ID
    name: string;        // Original filename
    mimeType: string;    // MIME type of the file
    createdAt: string;   // ISO 8601 timestamp
    updatedAt: string;   // ISO 8601 timestamp
    url: string | null;  // Source URL if provided
  };
}

Example Response

{
  "status": "success",
  "result": {
    "id": "att_abc123def456",
    "name": "updated-report.pdf",
    "mimeType": "application/pdf",
    "createdAt": "2025-01-15T10:30:00.000Z",
    "updatedAt": "2025-01-20T14:45:00.000Z",
    "url": null
  }
}

File Validation Response (400 Bad Request)

If the replacement file fails validation, the API returns the reason in message:

{
  "message": "The file \"updated-report.pdf\" is declared as a PDF but its content does not start with the expected PDF header.",
  "code": "BAD_REQUEST"
}

Error Handling

try {
  const response = await updateAttachment(folderId, attachmentId, filePath);
} catch (error) {
  if (error.response) {
    console.error(error.response.data.message ?? "Update failed");
  }
}

Status	Meaning
400	Invalid request or file validation failure
401	Invalid or missing API key
403	API key does not have access to the Knowledge base
404	Knowledge base or attachment not found
408	Upload timed out
413	File exceeds the size limit
429	Rate limit exceeded
500	Unexpected server error
503	Storage capacity exceeded

Processing Status

After updating, the new file is processed asynchronously. Use the Retrieve Files endpoint to check processing status. The syncStatus field indicates the current state:

• UPLOADING - File is being uploaded
• UPLOADED - File is uploaded and queued for processing
• EXTRACTING - Text is being extracted from the file
• EMBEDDING - Embeddings are being generated
• SYNCED - File is ready for search
• ACTION_FAILED, EXTRACTION_FAILED, EMBEDDING_FAILED, TIMEOUT - Processing failed

Langdock intentionally blocks browser-origin requests to protect your API key and ensure your applications remain secure. For more information, please see our guide on API Key Best Practices.

Authorizations

Authorization · string · header · required

API key as Bearer token. Format "Bearer YOUR_API_KEY"

Path Parameters

folderId · string · required

The ID of the knowledge folder

Body

multipart/form-data

file · file

The new file to upload

url · string

URL that is shown to the user if the file is used in an answer

attachmentId · string

The ID of the attachment to update

Response

200

Attachment updated successfully