Rust – Add array in reqwest::blocking::multipart::Part

November 20, 2023

I need to send an array of images to an API using form-data, so I’m using a loop to add the images, but I’m getting an error.

fn main() {
    let json = r#"{
        "imgupload": ["/home/user/Pictures/image01.jpg", "/home/user/Pictures/image02.jpg"]
    }"#
    .to_string();

    let request = serde_json::from_str::<ProductRequest>(json.as_str()).unwrap();

    let mut form = reqwest::blocking::multipart::Form::new();

    let array = request.imgupload.unwrap();

    for file_path in array.iter() {
        let file_name = get_file_name(file_path);

        let part = get_request_part_from_file(&file_path, &file_name);

        form.part("imgupload[]", part);
    }
}

fn get_file_name(x: &String) -> String {
    let file_name = std::path::Path::new(x)
        .file_name()
        .unwrap()
        .to_str()
        .unwrap()
        .to_string();

    file_name
}

fn get_request_part_from_file(
    file_path: &String,
    file_name: &String,
) -> reqwest::blocking::multipart::Part {
    println!("{}", file_path);
    let part = reqwest::blocking::multipart::Part::file(file_path)
        .unwrap()
        .file_name(file_name.to_string());

    part
}

#[derive(Serialize, Deserialize, Debug, Clone)]
pub struct ProductRequest {
    #[serde(skip_serializing_if = "Option::is_none")]
    pub imgupload: Option<Vec<String>>,
}

But I get the following error in form.part("imgupload[]", part); when trying to add reqwest::blocking::multipart::Part

enter image description here

What is the correct way to resolve this?

>Solution :

The part method on reqwest::blocking::multipart::Form takes ownership of self and returns a new Form with the part added.

Since it takes ownership of self you can not re-use the form variable after calling .part on it.

To fix your code you can re-assign form to the new Form taht .part returns:

fn main() {
    let json = r#"{
        "imgupload": ["/home/user/Pictures/image01.jpg", "/home/user/Pictures/image02.jpg"]
    }"#
    .to_string();

    let request = serde_json::from_str::<ProductRequest>(json.as_str()).unwrap();

    let mut form = reqwest::blocking::multipart::Form::new();

    let array = request.imgupload.unwrap();

    for file_path in array.iter() {
        let file_name = get_file_name(file_path);

        let part = get_request_part_from_file(&file_path, &file_name);

        form = form.part("imgupload[]", part);
    }
}