206 Partial Content status code

 

The 206 Partial Content status code is used when a server successfully fulfills a partial request for content, such as when only a specific portion (or "range") of a resource (like a file or video) is requested. This status is commonly seen in applications where only part of a large resource is needed at a time, allowing clients to request content in chunks rather than downloading everything in one go.

Here’s how 206 Partial Content works:

Key Concepts of 206 Partial Content

1. Range Requests: When a client requests only a specific part of a file, it includes a Range header in its HTTP request. For example: Range: bytes=0-1023. This header indicates that the client wants the first 1024 bytes of the file.

2. Server Responds with Partial Content: If the server supports partial content delivery, it responds with:

• A 206 Partial Content status code.
• A Content-Range header specifying which part of the file is being sent back. For example:  Content-Range: bytes 0-1023/4096
• The requested portion of the file.

3. Use Cases of Partial Content

   • Video or Audio Streaming: When streaming media files, clients may request different parts of the file in sequence, or skip to specific segments, making 206 Partial Content essential.
   • Download Managers: Download managers split large files into segments, requesting each part individually. If the connection breaks, they can resume downloading only the missing segments rather than starting from scratch.
   • API Pagination: APIs can use partial content responses to provide data in chunks, useful for pagination, as clients can request a range of records instead of loading all records at once.

4. Client Handling of Partial Content: Upon receiving a 206 Partial Content response, the client:

   • Assembles multiple responses if downloading in chunks.
   • Manages requests and responses to handle ranges efficiently.

Example of 206 Partial Content

Suppose a client needs to download a 10 MB file but wants only the first 1 MB initially. Here’s how the request and response would look:

• Client Request:

GET /file.mp4 HTTP/1.1

Host: example.com

Range: bytes=0-1048575

• Server Response:

HTTP/1.1 206 Partial Content

Content-Range: bytes 0-1048575/10485760

Content-Length: 1048576

The client receives the first MB of the file. If it needs more, it can send another request with a new range, making the 206 Partial Content status code highly efficient for handling large resources or managing interrupted downloads.