pi-frame-server/src/api.rs

use axum::extract::Multipart;
use axum::http::StatusCode;
use axum::response::IntoResponse;
use axum::{extract::State, response::Response, routing::post, Router};
use image::ImageReader;
use std::io::Cursor;

use crate::display::EInkPanel;
use std::sync::{Arc, Mutex};

pub enum ImageFormFields {
    DitherType,
    ImageFile,
}

#[derive(Clone)]
pub struct Context {
    display: Arc<Mutex<Box<dyn EInkPanel + Send>>>,
}
impl Context {
    #[must_use]
    pub fn new(w: Box<dyn EInkPanel + Send>) -> Self {
        Self {
            display: Arc::new(Mutex::new(w)),
        }
    }
}

// Make our own error that wraps `anyhow::Error`.
struct AppError(anyhow::Error);

// Tell axum how to convert `AppError` into a response.
impl IntoResponse for AppError {
    fn into_response(self) -> Response {
        (
            StatusCode::INTERNAL_SERVER_ERROR,
            format!("Something went wrong: {}", self.0),
        )
            .into_response()
    }
}

// This enables using `?` on functions that return `Result<_, anyhow::Error>` to turn them into
// `Result<_, AppError>`. That way you don't need to do that manually.
impl<E> From<E> for AppError
where
    E: Into<anyhow::Error>,
{
    fn from(err: E) -> Self {
        Self(err.into())
    }
}

/// API routes for axum
/// Start with the basics: Send an image, crop it, dither, and upload.
/// we defer the upload to a separate task.
pub fn router() -> Router<Context> {
    Router::new().route("/setimage", post(set_image))
}

async fn set_image(
    State(ctx): State<Context>,
    mut parts: Multipart,
) -> Result<impl IntoResponse, AppError> {
    while let Some(field) = parts.next_field().await? {
        let name = field.name().expect("fields always have names").to_string();
        let data = field.bytes().await?;
        println!("Length of `{}` is {} bytes", name, data.len());
        if &name == "image" {
            let reader = ImageReader::new(Cursor::new(data))
                .with_guessed_format()
                .expect("Cursor io never fails");
            println!("Guessed format: {:?}", reader.format());
            let _image = reader.decode()?;
        }
    }
    Ok(())
}