---
type: API Endpoint
title: "Read chunk"
description: "Endpoints for reading a byte range or page of a file without downloading it."
tags: [api, terrain, endpoints, filesystem]
status: stable
generated: { by: process:okf-migration, at: 2026-07-29T00:00:00Z }
---
Reading a chunk of a file
-------------------------

__URL Path__: /secured/filesystem/read-chunk

This endpoint delegates to data-info's /data/:data-id/chunks/:position/:size, after looking up the UUID corresponding to the path it was passed.

__HTTP Method__: POST

__Error Codes___: ERR_DOES_NOT_EXIST, ERR_NOT_READABLE, ERR_NOT_A_USER

__Request Query Parameters___:

__Request Body__:

    {
        "path"       : "/iplant/home/wregglej/testfile",
        "position"   : "20",
        "chunk-size" : "7"
    }

__Response__:

    {
        "path"       : "/iplant/home/wregglej/testfile",
        "user"       : "wregglej",
        "start"      : "20",
        "chunk-size" : "7",
        "file-size"  : "33",
        "chunk"      : "0\n12345"
    }

__Curl Command__:

    curl -H "$AUTH_HEADER" -H "Content-Type:application/json" -d '{"path" : "/iplant/home/wregglej/testfile", "position" : "20", "chunk-size" : "7"}' http://127.0.0.1:31360/secured/filesystem/read-chunk

Notes:
* 'position' and 'chunk-size' are both in bytes.
* 'position' and 'chunk-size' must be parseable as longs.
* 'start', 'chunk-size', and 'file-size' in the response are all in bytes.
* 'start', 'chunk-size', amd 'file-size' should all be parseable as longs.
* The byte at 'position' is not included in the response. The chunk begins at position + 1.