improve robustness and error feedback

Author: simschla

lib/src/main/java/com/diffplug/spotless/npm/SimpleRestClient.java

@@ -19,6 +19,7 @@
 
 import java.io.BufferedInputStream;
 import java.io.IOException;
+import java.io.InputStream;
 import java.io.OutputStream;
 import java.net.HttpURLConnection;
 import java.net.URL;
@@ -67,7 +68,7 @@ String postJson(String endpoint, String rawJson) throws SimpleRestException {
 			int status = con.getResponseCode();
 
 			if (status != 200) {
-				throw new SimpleRestResponseException(status, con.getResponseMessage(), "Unexpected response status code.");
+				throw new SimpleRestResponseException(status, readError(con), "Unexpected response status code at " + endpoint);
 			}
 
 			String response = readResponse(con);
@@ -77,8 +78,16 @@ String postJson(String endpoint, String rawJson) throws SimpleRestException {
 		}
 	}
 
+	private String readError(HttpURLConnection con) throws IOException {
+		return readInputStream(con.getErrorStream());
+	}
+
 	private String readResponse(HttpURLConnection con) throws IOException {
-		try (BufferedInputStream input = new BufferedInputStream(con.getInputStream())) {
+		return readInputStream(con.getInputStream());
+	}
+
+	private String readInputStream(InputStream inputStream) throws IOException {
+		try (BufferedInputStream input = new BufferedInputStream(inputStream)) {
 			return NpmResourceHelper.readUtf8StringFromInputStream(input);
 		}
 	}
@@ -121,7 +130,7 @@ public String getExceptionMessage() {
 
 		@Override
 		public String getMessage() {
-			return String.format("%s: %s (%s)", getStatusCode(), getResponseMessage(), getExceptionMessage());
+			return String.format("%s [HTTP %s] -- (%s)", getExceptionMessage(), getStatusCode(), getResponseMessage());
 		}
 	}
 

lib/src/main/resources/com/diffplug/spotless/npm/prettier-serve.js

@@ -40,18 +40,27 @@ app.post("/prettier/config-options", (req, res) => {
 			.resolveConfig(undefined, { config: prettier_config_path })
 			.then(options => {
 				var mergedConfigOptions = mergeConfigOptions(options, prettier_config_options);
+				res.set("Content-Type", "application/json")
 				res.json(mergedConfigOptions);
 			})
 			.catch(reason => res.status(501).send("Exception while resolving config_file_path: " + reason));
 		return;
 	}
+	res.set("Content-Type", "application/json")
 	res.json(prettier_config_options);
 });
 
 app.post("/prettier/format", (req, res) => {
 	var format_data = req.body;
 
-	var formatted_file_content = prettier.format(format_data.file_content, format_data.config_options);
+	var formatted_file_content = "";
+	try {
+		console.log("format_data", format_data);
+		formatted_file_content = prettier.format(format_data.file_content, format_data.config_options);
+	} catch(err) {
+		res.status(501).send("Error while formatting: " + err);
+		return;
+	}
 	res.set("Content-Type", "text/plain");
 	res.send(formatted_file_content);
 });

lib/src/main/resources/com/diffplug/spotless/npm/tsfmt-serve.js

@@ -55,5 +55,7 @@ app.post("/tsfmt/format", (req, res) => {
 		}
 		res.set("Content-Type", "text/plain");
 		res.send(resultMap.dest);
+	}).catch(reason => {
+		res.status(501).send(reason);
 	});
 });