fix: meaningful error message

Fixes #55
uetchy · Jan 5, 2021 · 2cdf86d · 2cdf86d
1 parent b33b2b0
commit 2cdf86d
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Showing 3 changed files with 46 additions and 8 deletions.
diff --git a/PolyglotSafariExtension/SafariExtensionHandler.swift b/PolyglotSafariExtension/SafariExtensionHandler.swift
@@ -4,6 +4,7 @@ import SafariServices
 struct MessageType {
   static let SendSettings = "settingsReceived"
   static let SendTranslation = "translated"
+  static let SendError = "error"
   static let PerformTranslation = "performTranslation"
 }
 
@@ -58,14 +59,19 @@ class SafariExtensionHandler: SFSafariExtensionHandler {
     let sourceLanguage = ud.string(forKey: SettingsKey.SourceLanguage) ?? "auto"
     let targetLanguage = ud.string(forKey: SettingsKey.TargetLanguage) ?? "en"
 
-    googleTranslate(text, sourceLanguage: sourceLanguage, targetLanguage: targetLanguage) { translationResult in
+    googleTranslate(text, sourceLanguage: sourceLanguage, targetLanguage: targetLanguage, completionHandler: { translationResult in
       page.dispatchMessageToScript(withName: MessageType.SendTranslation, userInfo: [
         "translation": translationResult["translation"] ?? "",
         "dictionary": translationResult["dictionary"] ?? [],
         "synonyms": translationResult["synonyms"] ?? [],
         "id": id,
       ])
-    }
+    }, errorHandler: { errorMessage in
+      page.dispatchMessageToScript(withName: MessageType.SendError, userInfo: [
+        "error": errorMessage,
+        "id": id,
+      ])
+    })
   }
 
   // This method will be called when your toolbar item is clicked.

diff --git a/PolyglotSafariExtension/Sources/content.ts b/PolyglotSafariExtension/Sources/content.ts
@@ -60,6 +60,11 @@ interface ReceivedTranslation {
   id: string;
 }
 
+interface UpstreamError {
+  error: string;
+  id: string;
+}
+
 enum RequestMessageType {
   RequestSettings = "getSettings",
   Translate = "translate",
@@ -68,6 +73,7 @@ enum RequestMessageType {
 enum ResponseMessageType {
   SettingsReceived = "settingsReceived",
   TranslationReceived = "translated",
+  ErrorOccured = "error",
   PerformTranslation = "performTranslation",
 }
 
@@ -102,6 +108,9 @@ function handleMessage(msg: SafariExtensionMessageEvent): void {
     case ResponseMessageType.TranslationReceived:
       translationHandler(msg.message);
       break;
+    case ResponseMessageType.ErrorOccured:
+      translationErrorHandler(msg.message);
+      break;
     case ResponseMessageType.PerformTranslation:
       performTranslation(); // TODO: support iframe
       break;
@@ -120,6 +129,23 @@ function settingsHandler(received: ReceivedSettings): void {
   console.debug(settings);
 }
 
+function translationErrorHandler(message: UpstreamError) {
+  if (message.id !== window.location.href) return;
+  const args = {
+    error: message.error,
+  };
+  const result = Mustache.render(
+    `
+  <div class="polyglot__inner">
+  <div class="polyglot__translation">
+    {{{error}}}
+  </div>
+  </div>`,
+    args
+  );
+  showPanel(result);
+}
+
 function translationHandler(message: ReceivedTranslation): void {
   if (message.id !== window.location.href) return;
 

diff --git a/PolyglotSafariExtension/Translator.swift b/PolyglotSafariExtension/Translator.swift
@@ -1,7 +1,7 @@
 import Alamofire
 import Foundation
 
-func googleTranslate(_ text: String, sourceLanguage: String, targetLanguage: String, completionHandler: @escaping (NSDictionary) -> Void) {
+func googleTranslate(_ text: String, sourceLanguage: String, targetLanguage: String, completionHandler: @escaping (NSDictionary) -> Void, errorHandler: @escaping (String) -> Void) {
   let endpoint: String = "https://translate.googleapis.com/translate_a/single?dt=t&dt=ss"
   let params: Alamofire.Parameters = [
     "client": "gtx",
@@ -17,21 +17,27 @@ func googleTranslate(_ text: String, sourceLanguage: String, targetLanguage: Str
     .validate(statusCode: 200 ..< 300)
     .responseJSON { response in
       if response.result.error != nil {
-        NSLog(response.result.error?.localizedDescription ?? "")
-        return
+        let errorMessage = response.result.error?.localizedDescription ?? ""
+        NSLog(errorMessage)
+        if let statusCode = response.response?.statusCode, statusCode == 429 {
+          return errorHandler("The API rate limit has been exceeded. Please try again later.")
+        }
+        return errorHandler(errorMessage)
       }
 
       guard let json = response.result.value as? NSDictionary,
-        let sentences = json["sentences"] as? NSArray else {
-        return
+            let sentences = json["sentences"] as? NSArray
+      else {
+        return errorHandler("Illegal JSON response")
       }
 
       let result: NSMutableDictionary = [:]
 
       // Translation
       result["translation"] = sentences.compactMap { (item) -> String? in
         guard let item = item as? NSDictionary,
-          let text = item["trans"] as? String else {
+              let text = item["trans"] as? String
+        else {
           return nil
         }
         return text