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)
+}

src/pages/api/mod.rs

@@ -5,6 +5,8 @@ pub mod exports;
 mod providers;
 mod scholarships;
 pub mod students;
+pub mod files;
+mod tokens;
 
 pub use admin::*;
 pub use comparisons::*;

src/pages/api/tokens.rs

@@ -0,0 +1,50 @@
+#[cfg(feature = "ssr")]
+use jsonwebtoken::{jwk::JwkSet, DecodingKey};
+use leptos::prelude::*;
+use crate::common::UserClaims;
+
+#[cfg(feature = "ssr")]
+pub async fn fetch_jwks(user_pool_id: String, region: String) -> Result<JwkSet, ServerFnError> {
+    let request_url = format!(
+        "https://cognito-idp.{}.amazonaws.com/{}/.well-known/jwks.json",
+        region,
+        user_pool_id
+    );
+
+    let jwks = reqwest::get(&request_url).await?
+        .json::<JwkSet>()
+        .await?;
+
+    Ok(jwks)
+}
+
+/// Validates a JWT, and, if successful, decodes it into a series of user claims.
+#[cfg(feature = "ssr")]
+pub async fn validate_and_get_token_info(token: String) -> Result<UserClaims, ServerFnError> {
+    use jsonwebtoken::{decode, Algorithm, Validation};
+
+    let jwks = fetch_jwks("us-east-1_Lfjuy5zaM".into(), "us-east-1".into()).await?;
+
+    let validation = Validation::new(Algorithm::RS256);
+    // validation.set_audience(&["scholarships-rs"]);
+
+    let header = jsonwebtoken::decode_header(&token)
+        .map_err(|e| ServerFnError::new(format!("Invalid token header: {e}")))?;
+
+    let kid = header.kid.ok_or_else(|| ServerFnError::new("Missing kid header"))?;
+
+    let jwk = jwks.find(&kid)
+        .ok_or_else(|| ServerFnError::new("Couldn't find matching key in JWKS"))?;
+
+    let token_data = decode::<UserClaims>(
+        &token,
+        &DecodingKey::from_jwk(&jwk)?,
+        &validation
+    ).map_err(|_| ServerFnError::new("Invalid token found".to_string()))?;
+
+    if token_data.claims.token_use != "access" {
+        return Err(ServerFnError::new("Token type mismatch"));
+    }
+
+    Ok(token_data.claims)
+}