Derive Macro actix_multipart::form::MultipartForm

#[derive(MultipartForm)]
{
    // Attributes available to this derive:
    #[multipart]
}

Available on crate feature derive only.

Implements MultipartCollect for a struct so that it can be used with the MultipartForm extractor.

Basic Use

Each field type should implement the FieldReader trait:

use actix_multipart::form::{tempfile::TempFile, text::Text, MultipartForm};

#[derive(MultipartForm)]
struct ImageUpload {
    description: Text<String>,
    timestamp: Text<i64>,
    image: TempFile,
}

Optional and List Fields

You can also use Vec<T> and Option<T> provided that T: FieldReader.

A [Vec] field corresponds to an upload with multiple parts under the same field name.

use actix_multipart::form::{tempfile::TempFile, text::Text, MultipartForm};

#[derive(MultipartForm)]
struct Form {
    category: Option<Text<String>>,
    files: Vec<TempFile>,
}

Field Renaming

You can use the #[multipart(rename = "foo")] attribute to receive a field by a different name.

use actix_multipart::form::{tempfile::TempFile, MultipartForm};

#[derive(MultipartForm)]
struct Form {
    #[multipart(rename = "files[]")]
    files: Vec<TempFile>,
}

Field Limits

You can use the #[multipart(limit = "<size>")] attribute to set field level limits. The limit string is parsed using parse_size.

Note: the form is also subject to the global limits configured using MultipartFormConfig.

use actix_multipart::form::{tempfile::TempFile, text::Text, MultipartForm};

#[derive(MultipartForm)]
struct Form {
    #[multipart(limit = "2 KiB")]
    description: Text<String>,

    #[multipart(limit = "512 MiB")]
    files: Vec<TempFile>,
}

Unknown Fields

By default fields with an unknown name are ignored. They can be rejected using the #[multipart(deny_unknown_fields)] attribute:

#[derive(MultipartForm)]
#[multipart(deny_unknown_fields)]
struct Form { }

Duplicate Fields

The behaviour for when multiple fields with the same name are received can be changed using the #[multipart(duplicate_field = "<behavior>")] attribute:

• “ignore”: (default) Extra fields are ignored. I.e., the first one is persisted.
• “deny”: A MultipartError::UnsupportedField error response is returned.
• “replace”: Each field is processed, but only the last one is persisted.

Note that Vec fields will ignore this option.

#[derive(MultipartForm)]
#[multipart(duplicate_field = "deny")]
struct Form { }