`write_file`

Write content to a file, creating it if it does not exist. Supports both text and binary output.

Parameters

pathstringrequired: Destination file path. Supports ${ctx.key} interpolation.
contentstringdefault "": The text to write. Supports ${ctx.key} interpolation. Ignored when source_key is set.
source_keystring: Context key whose string value supplies the content. Use with encoding = "base64" to write binary data from context.
encodingstringdefault "text": "text" writes UTF-8 bytes. "base64" decodes the content from base64 before writing (produces binary output).
appendbooldefault false: When true, content is appended to the file instead of overwriting it. The file is created if it does not exist.

When source_key is provided, the node reads the value from the workflow context instead of using content. This is useful for writing data produced by earlier steps (e.g., a base64-encoded image from an HTTP response).

Context Output

write_file_path — The resolved file path (after interpolation).
write_file_success — true when the write completed successfully.

Examples

Write a text file

local flow = Flow.new("write_demo")

flow:step("write", nodes.write_file({
    path = "/tmp/ironflow_test.txt",
    content = "Hello from IronFlow!\nTimestamp: ${ctx.timestamp}"
}))

flow:step("append", nodes.write_file({
    path = "/tmp/ironflow_test.txt",
    content = "\nAppended line.",
    append = true
})):depends_on("write")

return flow

Write a binary file from context

local flow = Flow.new("write_binary")

-- Assume a previous step stored base64 image data in ctx.img_data
flow:step("save_image", nodes.write_file({
    path = "/tmp/output.png",
    source_key = "img_data",
    encoding = "base64"
}))

return flow