axum_typed_multipart 0.1.0

Helper library for the axum framework designed to allow you to parse the multipart/form-data body of the supplied request into an arbitrary struct.

Usage

Getting started

To get started you will need to define a struct with the desired fields and implement the TryFromMultipart trait. In the vast majority of cases you will want to use the derive macro to generate the implementation automatically. To be able to derive the implementation every field must implement the TryFromField trait. The trait is implemented by default for all primitive types, [String], and [Vec<u8>] in case you just want to access the raw bytes.

If the request body is malformed or it does not contain the necessary data the request will be aborted with an error.

use axum_typed_multipart::{TryFromMultipart, TypedMultipart};

#[derive(TryFromMultipart)]
struct RequestData {
first_name: String,
last_name: String,
}

async fn handler(
TypedMultipart(RequestData { first_name, last_name }): TypedMultipart<RequestData>,
) {
// All fields are guaranteed to be populated.
}

Optional fields

If a field is declared as an [Option] the value will default to [Option::None] when the field is missing from the request body.

use axum_typed_multipart::TryFromMultipart;

#[derive(TryFromMultipart)]
struct RequestData {
first_name: Option<String>,
}

Renaming fields

If you would like to assign a custom name to the struct field you can use the field_name parameter in the form_data attribute.

use axum_typed_multipart::TryFromMultipart;

#[derive(TryFromMultipart)]
struct RequestData {
#[form_data(field_name = "input_file")]
name: Option<String>,
}

Field metadata

If you need access to the field metadata (e.g. the request headers) you can use the FieldData struct to wrap your field.

use axum_typed_multipart::{FieldData, TryFromMultipart, TypedMultipart};

#[derive(TryFromMultipart)]
struct RequestData {
image: FieldData<Vec<u8>>,
}

async fn handler(TypedMultipart(RequestData { image }): TypedMultipart<RequestData>) {
println!("content_type = {}", image.metadata.content_type.unwrap());
}

Large uploads

For large file uploads you can save the contents of the file to the file system using the TempFile helper. This will stream the field body to the file system allowing you to save the contents later.

use axum_typed_multipart::{FieldData, TempFile, TryFromMultipart, TypedMultipart};

#[derive(TryFromMultipart)]
struct RequestData {
image: FieldData<TempFile>,
}

async fn handler(TypedMultipart(RequestData { image }): TypedMultipart<RequestData>) {
image.contents.persist("/data/file.bin", false).await.unwrap();
}