support redirection on s3 endpoint

1 files changed, 253 insertions, 63 deletions

diff --git a/src/web/web_server.rs b/src/web/web_server.rs
index 69939f65..d8ce0460 100644
--- a/src/web/web_server.rs
+++ b/src/web/web_server.rs
@@ -28,6 +28,7 @@ use garage_api::s3::error::{
 };
 use garage_api::s3::get::{handle_get_without_ctx, handle_head_without_ctx};
 
+use garage_model::bucket_table::RoutingRule;
 use garage_model::garage::Garage;
 
 use garage_table::*;
@@ -234,26 +235,32 @@ impl WebServer {
 		// Get path
 		let path = req.uri().path().to_string();
 		let index = &website_config.index_document;
-		let (key, may_redirect) = path_to_keys(&path, index)?;
+		let routing_result = path_to_keys(&path, index, &[])?;
 
 		debug!(
-			"Selected bucket: \"{}\" {:?}, target key: \"{}\", may redirect to: {:?}",
-			bucket_name, bucket_id, key, may_redirect
+			"Selected bucket: \"{}\" {:?}, routing to {:?}",
+			bucket_name, bucket_id, routing_result,
 		);
 
-		let ret_doc = match *req.method() {
-			Method::OPTIONS => handle_options_for_bucket(req, &bucket_params)
+		let ret_doc = match (req.method(), routing_result.main_target()) {
+			(&Method::OPTIONS, _) => handle_options_for_bucket(req, &bucket_params)
 				.map_err(ApiError::from)
 				.map(|res| res.map(|_empty_body: EmptyBody| empty_body())),
-			Method::HEAD => {
-				handle_head_without_ctx(self.garage.clone(), req, bucket_id, &key, None).await
+			(_, Err((url, code))) => Ok(Response::builder()
+				.status(code)
+				.header("Location", url)
+				.body(empty_body())
+				.unwrap()),
+			(&Method::HEAD, Ok((key, code))) => {
+				handle_head_without_ctx(self.garage.clone(), req, bucket_id, key, code, None).await
 			}
-			Method::GET => {
+			(&Method::GET, Ok((key, code))) => {
 				handle_get_without_ctx(
 					self.garage.clone(),
 					req,
 					bucket_id,
-					&key,
+					key,
+					code,
 					None,
 					Default::default(),
 				)
@@ -262,16 +269,68 @@ impl WebServer {
 			_ => Err(ApiError::bad_request("HTTP method not supported")),
 		};
 
-		// Try implicit redirect on error
-		let ret_doc_with_redir = match (&ret_doc, may_redirect) {
-			(Err(ApiError::NoSuchKey), ImplicitRedirect::To { key, url })
-				if self.check_key_exists(bucket_id, key.as_str()).await? =>
-			{
-				Ok(Response::builder()
-					.status(StatusCode::FOUND)
-					.header("Location", url)
-					.body(empty_body())
-					.unwrap())
+		// Try handling errors if bucket configuration provided fallbacks
+		let ret_doc_with_redir = match (&ret_doc, &routing_result) {
+			(
+				Err(ApiError::NoSuchKey),
+				RoutingResult::LoadOrRedirect {
+					redirect_if_exists,
+					redirect_url,
+					redirect_code,
+					..
+				},
+			) => {
+				let redirect = if let Some(redirect_key) = redirect_if_exists {
+					self.check_key_exists(bucket_id, redirect_key.as_str())
+						.await?
+				} else {
+					true
+				};
+				if redirect {
+					Ok(Response::builder()
+						.status(redirect_code)
+						.header("Location", redirect_url)
+						.body(empty_body())
+						.unwrap())
+				} else {
+					ret_doc
+				}
+			}
+			(
+				Err(ApiError::NoSuchKey),
+				RoutingResult::LoadOrAlternativeError {
+					redirect_key,
+					redirect_code,
+					..
+				},
+			) => {
+				match *req.method() {
+					Method::HEAD => {
+						handle_head_without_ctx(
+							self.garage.clone(),
+							req,
+							bucket_id,
+							redirect_key,
+							*redirect_code,
+							None,
+						)
+						.await
+					}
+					Method::GET => {
+						handle_get_without_ctx(
+							self.garage.clone(),
+							req,
+							bucket_id,
+							redirect_key,
+							*redirect_code,
+							None,
+							Default::default(),
+						)
+						.await
+					}
+					// we shouldn't ever reach here
+					_ => Err(ApiError::bad_request("HTTP method not supported")),
+				}
 			}
 			_ => ret_doc,
 		};
@@ -307,6 +366,7 @@ impl WebServer {
 					&req2,
 					bucket_id,
 					&error_document,
+					error.http_status_code(),
 					None,
 					Default::default(),
 				)
@@ -323,8 +383,6 @@ impl WebServer {
 							error
 						);
 
-						*error_doc.status_mut() = error.http_status_code();
-
 						// Preserve error message in a special header
 						for error_line in error.to_string().split('\n') {
 							if let Ok(v) = HeaderValue::from_bytes(error_line.as_bytes()) {
@@ -371,9 +429,44 @@ fn error_to_res(e: Error) -> Response<BoxBody<Error>> {
 }
 
 #[derive(Debug, PartialEq)]
-enum ImplicitRedirect {
-	No,
-	To { key: String, url: String },
+enum RoutingResult {
+	// Load a key and use `code` as status, or fallback to normal 404 handler if not found
+	LoadKey {
+		key: String,
+		code: StatusCode,
+	},
+	// Load a key and use `200` as status, or fallback with a redirection using `redirect_code`
+	// as status
+	LoadOrRedirect {
+		key: String,
+		redirect_if_exists: Option<String>,
+		redirect_url: String,
+		redirect_code: StatusCode,
+	},
+	// Load a key and use `200` as status, or fallback by loading a different key and use
+	// `redirect_code` as status
+	LoadOrAlternativeError {
+		key: String,
+		redirect_key: String,
+		redirect_code: StatusCode,
+	},
+	// Send an http redirect with `code` as status
+	Redirect {
+		url: String,
+		code: StatusCode,
+	},
+}
+
+impl RoutingResult {
+	// return Ok((key_to_deref, status_code)) or Err((redirect_target, status_code))
+	fn main_target(&self) -> Result<(&str, StatusCode), (&str, StatusCode)> {
+		match self {
+			RoutingResult::LoadKey { key, code } => Ok((key, *code)),
+			RoutingResult::LoadOrRedirect { key, .. } => Ok((key, StatusCode::OK)),
+			RoutingResult::LoadOrAlternativeError { key, .. } => Ok((key, StatusCode::OK)),
+			RoutingResult::Redirect { url, code } => Err((url, *code)),
+		}
+	}
 }
 
 /// Path to key
@@ -383,35 +476,128 @@ enum ImplicitRedirect {
 /// which is also AWS S3 behavior.
 ///
 /// Check: https://docs.aws.amazon.com/AmazonS3/latest/userguide/IndexDocumentSupport.html
-fn path_to_keys<'a>(path: &'a str, index: &str) -> Result<(String, ImplicitRedirect), Error> {
+fn path_to_keys<'a>(
+	path: &'a str,
+	index: &str,
+	routing_rules: &[RoutingRule],
+) -> Result<RoutingResult, Error> {
 	let path_utf8 = percent_encoding::percent_decode_str(path).decode_utf8()?;
 
 	let base_key = match path_utf8.strip_prefix("/") {
 		Some(bk) => bk,
 		None => return Err(Error::BadRequest("Path must start with a / (slash)".into())),
 	};
+
 	let is_bucket_root = base_key.len() == 0;
 	let is_trailing_slash = path_utf8.ends_with("/");
 
-	match (is_bucket_root, is_trailing_slash) {
-		// It is not possible to store something at the root of the bucket (ie. empty key),
-		// the only option is to fetch the index
-		(true, _) => Ok((index.to_string(), ImplicitRedirect::No)),
-
-		// "If you create a folder structure in your bucket, you must have an index document at each level. In each folder, the index document must have the same name, for example, index.html. When a user specifies a URL that resembles a folder lookup, the presence or absence of a trailing slash determines the behavior of the website. For example, the following URL, with a trailing slash, returns the photos/index.html index document."
-		(false, true) => Ok((format!("{base_key}{index}"), ImplicitRedirect::No)),
-
-		// "However, if you exclude the trailing slash from the preceding URL, Amazon S3 first looks for an object photos in the bucket. If the photos object is not found, it searches for an index document, photos/index.html. If that document is found, Amazon S3 returns a 302 Found message and points to the photos/ key. For subsequent requests to photos/, Amazon S3 returns photos/index.html. If the index document is not found, Amazon S3 returns an error."
-		(false, false) => Ok((
-			base_key.to_string(),
-			ImplicitRedirect::To {
-				key: format!("{base_key}/{index}"),
-				url: format!("{path}/"),
-			},
-		)),
+	let key = if is_bucket_root || is_trailing_slash {
+		// we can't store anything at the root, so we need to query the index
+		// if the key end with a slash, we always query the index
+		format!("{base_key}{index}")
+	} else {
+		// if the key doesn't end with `/`, leave it unmodified
+		base_key.to_string()
+	};
+
+	let mut routing_rules_iter = routing_rules.iter();
+	let key = loop {
+		let Some(routing_rule) = routing_rules_iter.next() else {
+			break key;
+		};
+
+		let Ok(status_code) = StatusCode::from_u16(routing_rule.redirect.http_redirect_code) else {
+			continue;
+		};
+		if let Some(condition) = &routing_rule.condition {
+			let suffix = if let Some(prefix) = &condition.prefix {
+				let Some(suffix) = key.strip_prefix(prefix) else {
+					continue;
+				};
+				Some(suffix)
+			} else {
+				None
+			};
+			let target = routing_rule.redirect.compute_target(suffix);
+			let query_alternative_key =
+				status_code == StatusCode::OK || status_code == StatusCode::NOT_FOUND;
+			let redirect_on_error =
+				condition.http_error_code == Some(StatusCode::NOT_FOUND.as_u16());
+			match (query_alternative_key, redirect_on_error) {
+				(false, false) => {
+					return Ok(RoutingResult::Redirect {
+						url: target,
+						code: status_code,
+					})
+				}
+				(true, false) => {
+					if status_code == StatusCode::OK {
+						break target;
+					} else {
+						return Ok(RoutingResult::LoadKey {
+							key: target,
+							code: status_code,
+						});
+					}
+				}
+				(false, true) => {
+					return Ok(RoutingResult::LoadOrRedirect {
+						key,
+						redirect_if_exists: None,
+						redirect_url: target,
+						redirect_code: status_code,
+					});
+				}
+				(true, true) => {
+					return Ok(RoutingResult::LoadOrAlternativeError {
+						key,
+						redirect_key: target,
+						redirect_code: status_code,
+					});
+				}
+			}
+		} else {
+			let target = routing_rule.redirect.compute_target(None);
+			return Ok(RoutingResult::Redirect {
+				url: target,
+				code: status_code,
+			});
+		}
+	};
+
+	if is_bucket_root || is_trailing_slash {
+		Ok(RoutingResult::LoadKey {
+			key,
+			code: StatusCode::OK,
+		})
+	} else {
+		Ok(RoutingResult::LoadOrRedirect {
+			redirect_if_exists: Some(format!("{key}/{index}")),
+			key,
+			// we can't use `path` because key might have changed substentially in case of
+			// routing rules
+			redirect_url: percent_encoding::percent_encode(
+				format!("{path}/").as_bytes(),
+				PATH_ENCODING_SET,
+			)
+			.to_string(),
+			redirect_code: StatusCode::FOUND,
+		})
 	}
 }
 
+// per https://url.spec.whatwg.org/#path-percent-encode-set
+const PATH_ENCODING_SET: &percent_encoding::AsciiSet = &percent_encoding::CONTROLS
+	.add(b' ')
+	.add(b'"')
+	.add(b'#')
+	.add(b'<')
+	.add(b'>')
+	.add(b'?')
+	.add(b'`')
+	.add(b'{')
+	.add(b'}');
+
 #[cfg(test)]
 mod tests {
 	use super::*;
@@ -419,35 +605,39 @@ mod tests {
 	#[test]
 	fn path_to_keys_test() -> Result<(), Error> {
 		assert_eq!(
-			path_to_keys("/file%20.jpg", "index.html")?,
-			(
-				"file .jpg".to_string(),
-				ImplicitRedirect::To {
-					key: "file .jpg/index.html".to_string(),
-					url: "/file%20.jpg/".to_string()
-				}
-			)
+			path_to_keys("/file%20.jpg", "index.html", &[])?,
+			RoutingResult::LoadOrRedirect {
+				key: "file .jpg".to_string(),
+				redirect_url: "/file%20.jpg/".to_string(),
+				redirect_if_exists: Some("file .jpg/index.html".to_string()),
+				redirect_code: StatusCode::FOUND,
+			}
 		);
 		assert_eq!(
-			path_to_keys("/%20t/", "index.html")?,
-			(" t/index.html".to_string(), ImplicitRedirect::No)
+			path_to_keys("/%20t/", "index.html", &[])?,
+			RoutingResult::LoadKey {
+				key: " t/index.html".to_string(),
+				code: StatusCode::OK
+			}
 		);
 		assert_eq!(
-			path_to_keys("/", "index.html")?,
-			("index.html".to_string(), ImplicitRedirect::No)
+			path_to_keys("/", "index.html", &[])?,
+			RoutingResult::LoadKey {
+				key: "index.html".to_string(),
+				code: StatusCode::OK
+			}
 		);
 		assert_eq!(
-			path_to_keys("/hello", "index.html")?,
-			(
-				"hello".to_string(),
-				ImplicitRedirect::To {
-					key: "hello/index.html".to_string(),
-					url: "/hello/".to_string()
-				}
-			)
+			path_to_keys("/hello", "index.html", &[])?,
+			RoutingResult::LoadOrRedirect {
+				key: "hello".to_string(),
+				redirect_url: "/hello/".to_string(),
+				redirect_if_exists: Some("hello/index.html".to_string()),
+				redirect_code: StatusCode::FOUND,
+			}
 		);
-		assert!(path_to_keys("", "index.html").is_err());
-		assert!(path_to_keys("i/am/relative", "index.html").is_err());
+		assert!(path_to_keys("", "index.html", &[]).is_err());
+		assert!(path_to_keys("i/am/relative", "index.html", &[]).is_err());
 		Ok(())
 	}
 }