feat: implement file upload functionality

src/pages/api/files.rs

@@ -0,0 +1,60 @@
+use leptos::prelude::*;
+use server_fn::codec::{MultipartFormData, MultipartData};
+use leptos::logging::debug_log;
+
+#[server(input = MultipartFormData)]
+pub async fn upload_file(
+    data: MultipartData
+) -> Result<(), ServerFnError> {
+    use std::path::PathBuf;
+    use crate::pages::api::tokens::validate_and_get_token_info;
+    use crate::utils::server::create_aws_config;
+
+    let mut multipart = data.into_inner().unwrap();
+
+    let mut file_name = String::new();
+    let mut file_bytes = Vec::<u8>::new();
+    let mut form_id = String::new();
+    let mut access_token = String::new();
+
+    while let Ok(Some(field)) = multipart.next_field().await {
+        let field_name = field.name().unwrap_or_default();
+
+        match field_name {
+            "access_token" => access_token = field.text().await?,
+            "form_id" => form_id = field.text().await?,
+            _ => {
+                // NOTE: If there are multiple files put here the function will only upload the last
+                // one in the data.
+                // We should likely use chunk streaming in the future, for safety.
+                file_name = field.file_name()
+                    .ok_or(ServerFnError::new("Couldn't find file name"))?
+                    .to_owned();
+                file_bytes = field.bytes().await?.to_vec();
+            },
+        }
+    }
+
+    if access_token.is_empty() { return Err(ServerFnError::new("Missing access token")); }
+    if form_id.is_empty() { return Err(ServerFnError::new("Missing form ID")); }
+    if file_name.is_empty() { return Err(ServerFnError::new("Missing file")); }
+
+    let user_claims = validate_and_get_token_info(access_token).await?;
+    let subject = user_claims.subject;
+
+    let key = format!("{form_id}/{subject}/{file_name}");
+
+    debug_log!("Adding file to S3: {:?}", key);
+
+    let client = aws_sdk_s3::Client::new(&create_aws_config().await);
+
+    client
+        .put_object()
+        .bucket("leptos-scholarships")
+        .key(key)
+        .body(file_bytes.into())
+        .send()
+        .await
+        .map(|_| ())
+        .map_err(ServerFnError::from)
+}