From 7d114c7414c6fbb06d0772c3dbf936f757282086 Mon Sep 17 00:00:00 2001
From: Greg Johnston <greg.johnston@gmail.com>
Date: Mon, 15 Jan 2024 17:07:14 -0500
Subject: [PATCH] file upload example

---
 examples/server_fns_axum/Cargo.toml |  1 +
 examples/server_fns_axum/src/app.rs | 86 ++++++++++++++++++++++++-----
 2 files changed, 73 insertions(+), 14 deletions(-)

diff --git a/examples/server_fns_axum/Cargo.toml b/examples/server_fns_axum/Cargo.toml
index c23ec1ae3..fb1d7b762 100644
--- a/examples/server_fns_axum/Cargo.toml
+++ b/examples/server_fns_axum/Cargo.toml
@@ -27,6 +27,7 @@ thiserror = "1.0"
 wasm-bindgen = "0.2"
 serde_toml = "0.0.1"
 toml = "0.8.8"
+web-sys = { version = "0.3.67", features = ["FileList", "File"] }
 
 [features]
 hydrate = ["leptos/hydrate", "leptos_meta/hydrate", "leptos_router/hydrate"]
diff --git a/examples/server_fns_axum/src/app.rs b/examples/server_fns_axum/src/app.rs
index af9d4b5d0..dd5edb0fb 100644
--- a/examples/server_fns_axum/src/app.rs
+++ b/examples/server_fns_axum/src/app.rs
@@ -1,23 +1,16 @@
-use crate::error_template::ErrorTemplate;
-use http::{Request, Response};
 use leptos::{html::Input, *};
-use leptos_meta::{Link, Stylesheet};
-use leptos_router::*;
-use serde::{de::DeserializeOwned, Deserialize, Serialize};
-use server_fn::{
-    codec::{
-        Encoding, FromReq, FromRes, GetUrl, IntoReq, IntoRes, Rkyv, SerdeLite,
-    },
-    error::NoCustomError,
-    request::{browser::BrowserRequest, BrowserMockReq, ClientReq, Req},
-    response::{browser::BrowserResponse, ClientRes, Res},
-    rkyv::AlignedVec,
+use leptos_meta::{provide_meta_context, Link, Stylesheet};
+use leptos_router::{ActionForm, Route, Router, Routes};
+use server_fn::codec::{
+    GetUrl, MultipartData, MultipartFormData, Rkyv, SerdeLite,
 };
 #[cfg(feature = "ssr")]
 use std::sync::{
     atomic::{AtomicU8, Ordering},
     Mutex,
 };
+use wasm_bindgen::JsCast;
+use web_sys::{FormData, HtmlFormElement, SubmitEvent};
 
 #[component]
 pub fn TodoApp() -> impl IntoView {
@@ -49,7 +42,7 @@ pub fn HomePage() -> impl IntoView {
         <h2>"Alternative Encodings"</h2>
         <ServerFnArgumentExample/>
         <RkyvExample/>
-        <CustomEncoding/>
+        <FileUpload/>
     }
 }
 
@@ -310,3 +303,68 @@ pub fn RkyvExample() -> impl IntoView {
         </Transition>
     }
 }
+
+#[component]
+pub fn FileUpload() -> impl IntoView {
+    /// A simple file upload function, which does just returns the length of the file.
+    ///
+    /// On the server, this uses the `multer` crate, which provides a streaming API.
+    #[server(
+    input = MultipartFormData,
+)]
+    pub async fn file_length(
+        data: MultipartData,
+    ) -> Result<usize, ServerFnError> {
+        // `.into_inner()` returns the inner `multer` stream
+        // it is `None` if we call this on the client, but always `Some(_)` on the server, so is safe to
+        // unwrap
+        let mut data = data.into_inner().unwrap();
+
+        // this will just measure the total number of bytes uploaded
+        let mut count = 0;
+        while let Ok(Some(mut field)) = data.next_field().await {
+            println!("\n[NEXT FIELD]\n");
+            let name = field.name().unwrap_or_default().to_string();
+            println!("  [NAME] {name}");
+            while let Ok(Some(chunk)) = field.chunk().await {
+                let len = chunk.len();
+                count += len;
+                println!("      [CHUNK] {len}");
+                // in a real server function, you'd do something like saving the file here
+            }
+        }
+
+        Ok(count)
+    }
+
+    let upload_action = create_action(|data: &FormData| {
+        let data = data.clone();
+        // `MultipartData` implements `From<FormData>`
+        file_length(data.into())
+    });
+
+    view! {
+        <h3>File Upload</h3>
+        <p>Uploading files is fairly easy using multipart form data.</p>
+        <form on:submit=move |ev: SubmitEvent| {
+            ev.prevent_default();
+            let target = ev.target().unwrap().unchecked_into::<HtmlFormElement>();
+            let form_data = FormData::new_with_form(&target).unwrap();
+            upload_action.dispatch(form_data);
+        }>
+            <input type="file" name="file_to_upload"/>
+            <input type="submit"/>
+        </form>
+        <p>
+            {move || if upload_action.input().get().is_none() && upload_action.value().get().is_none() {
+                "Upload a file.".to_string()
+            } else if upload_action.pending().get() {
+                "Uploading...".to_string()
+            } else if let Some(Ok(value)) = upload_action.value().get() {
+                value.to_string()
+            } else {
+                format!("{:?}", upload_action.value().get())
+            }}
+        </p>
+    }
+}