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CC2 Device Documentation

File Operations

File operations are one‑shot devwork actions that create, read, update, delete, and move files on the device’s USB file system. All local paths may include a directory prefix (e.g., /cfg/config.json).

Important: The devwork envelope must wrap actions in an "actions" array:

{
  "devwork": {
    "actions": [
      {
        "a": "fcre",
        "p": {
          "file": "/config.json",
          "content": {
            "key": "value",
          },
        },
      },
    ],
  },
}
Action Description
fdld Download a file from a URL
fcre Create a file with optional content
fapp Append content to a file
fmv Move / rename a file
fdel Delete a file or directory
fmkd Create a directory
ffmt Format the entire USB filesystem
fget Retrieve a file or directory listing

fdld

Section titled “fdld”

Downloads a file from a URL and saves it to the local filesystem. A temporary file in /tmp is used during the download; on success it is renamed to the target path.

Configuration variables

  • a (Required, string): Must be fdld.
  • p (Required, object):
Parameter Type Required Description
url string yes HTTP/HTTPS URL to fetch
file string yes Local path to save to (parent directories must exist)

Response: The device sends an uplink message on completion.

Field Type Description
file string Local file path
res number 0 = OK, 1 = timeout, 2 = internal error, 3 = server error
httpres number HTTP status code (if available)
httplen number Content length from the HTTP server 
{
  "devwork": {
    "actions": [
      {
        "a": "fdld",
        "p": {
          "url": "https://example.com/config.json",
          "file": "/cfg/config.json",
        },
      },
    ],
  },
}

fcre

Section titled “fcre”

Creates a file with optional content. Any existing file at that path is discarded before writing.

Configuration variables

  • a (Required, string): Must be fcre.
  • p (Required, object):
Parameter Type Required Description
file string yes Local path to create
content string or object no Initial file content 
{
  "devwork": {
    "actions": [
      {
        "a": "fcre",
        "p": {
          "file": "/notes.txt",
          "content": "hello",
        },
      },
    ],
  },
}

fapp

Section titled “fapp”

Appends content to an existing file.

Configuration variables

  • a (Required, string): Must be fapp.
  • p (Required, object):
Parameter Type Required Description
file string yes Local path to append to
content string yes Data to append 
{
  "devwork": {
    "actions": [
      {
        "a": "fapp",
        "p": {
          "file": "/notes.txt",
          "content": " world",
        },
      },
    ],
  },
}

fmv

Section titled “fmv”

Moves or renames a file. The source and destination may be in different directories.

Configuration variables

  • a (Required, string): Must be fmv.
  • p (Required, object):
Parameter Type Required Description
src string yes Current file path
dst string yes New file path 
{
  "devwork": {
    "actions": [
      {
        "a": "fmv",
        "p": {
          "src": "/tmp/temp.json",
          "dst": "/cfg/live.json",
        },
      },
    ],
  },
}

fdel

Section titled “fdel”

Deletes a file or directory.

Configuration variables

  • a (Required, string): Must be fdel.
  • p (Required, object):
Parameter Type Required Description
path string yes Local file or directory to delete 
{
  "devwork": {
    "actions": [
      {
        "a": "fdel",
        "p": {
          "path": "/notes.txt",
        },
      },
    ],
  },
}

fmkd

Section titled “fmkd”

Creates a new directory.

Configuration variables

  • a (Required, string): Must be fmkd.
  • p (Required, object):
Parameter Type Required Description
path string yes Directory path to create 
{
  "devwork": {
    "actions": [
      {
        "a": "fmkd",
        "p": {
          "path": "/cfg",
        },
      },
    ],
  },
}

ffmt

Section titled “ffmt”

Formats the entire USB filesystem. This wipes all files and directories.

Configuration variables

  • a (Required, string): Must be ffmt.
  • p (Required, object):
Parameter Type Required Description
conf string yes Must be "YES" (confirmation string) 
{
  "devwork": {
    "actions": [
      {
        "a": "ffmt",
        "p": {
          "conf": "YES",
        },
      },
    ],
  },
}

fget

Section titled “fget”

Retrieves a file’s contents or a directory listing. The device responds with an uplink message.

Configuration variables

  • a (Required, string): Must be fget.
  • p (Required, object):
Parameter Type Required Description
path string yes Local file or directory path
asc boolean no Strip non‑ASCII bytes from file content
hex boolean no Send file content as a hex string

Response: The device sends an uplink message: { "devwork": { "fs": { "fget": { "isFile": true|false, "path": "<path>", "content": <file content or directory JSON> } } } }

Files larger than ~1 KB may be truncated in the JSON response.

{
  "devwork": {
    "actions": [
      {
        "a": "fget",
        "p": {
          "path": "/cfg/config.json",
        },
      },
    ],
  },
}
Section titled “Related”