improve auto-detect for batch requests with multiple languages

app/app.py

@@ -360,43 +360,61 @@ def create_app(args):
                 )
 
         if source_lang == "auto":
-            candidate_langs = detect_languages(q)
-
-            if args.debug:
-                print(candidate_langs)
-
-            source_lang = candidate_langs[0]["language"]
+            source_langs = []
+            if batch:
+              auto_detect_texts = q
+            else:
+              auto_detect_texts = [q]
+
+            overall_candidates = detect_languages(q)
+            
+            for text_to_check in auto_detect_texts:
+              if len(text_to_check) > 40:
+                candidate_langs = detect_languages(text_to_check)
+              else:
+                # Unable to accurately detect languages for short texts
+                candidate_langs = overall_candidates
+              source_langs.append(candidate_langs[0]["language"])
+
+              if args.debug:
+                  print(text_to_check, candidate_langs)
+                  print("Auto detected: %s" % candidate_langs[0]["language"])
+        else:
+          if batch:
+            source_langs = [source_lang for text in q]
+          else:
+            source_langs = [source_lang]
 
-            if args.debug:
-                print("Auto detected: %s" % source_lang)
+        src_langs = [next(iter([l for l in languages if l.code == source_lang]), None) for source_lang in source_langs]
+        
+        for idx, lang in enumerate(src_langs):
+          if lang is None:
+            abort(400, description="%s is not supported" % source_langs[idx])
 
-        src_lang = next(iter([l for l in languages if l.code == source_lang]), None)
         tgt_lang = next(iter([l for l in languages if l.code == target_lang]), None)
 
-        if src_lang is None:
-            abort(400, description="%s is not supported" % source_lang)
         if tgt_lang is None:
             abort(400, description="%s is not supported" % target_lang)
 
-        translator = src_lang.get_translation(tgt_lang)
-
         try:
             if batch:
+                results = []
+                for idx, text in enumerate(q):
+                  translator = src_langs[idx].get_translation(tgt_lang)
+                  results.append(translator.translate(
+                                transliterate(text, target_lang=source_langs[idx])
+                                ))
                 return jsonify(
                     {
-                        "translatedText": [
-                            translator.translate(
-                                transliterate(text, target_lang=source_lang)
-                            )
-                            for text in q
-                        ]
+                        "translatedText": results
                     }
                 )
             else:
+                translator = src_langs[0].get_translation(tgt_lang)
                 return jsonify(
                     {
                         "translatedText": translator.translate(
-                            transliterate(q, target_lang=source_lang)
+                            transliterate(q, target_lang=source_langs[0])
                         )
                     }
                 )

app/language.py

@@ -22,16 +22,19 @@ def detect_languages(text):
     candidates = []
     for t in text:
         try:
-            candidates.extend(Detector(t).languages)
+            d = Detector(t).languages
+            for i in range(len(d)):
+                d[i].text_length = len(t)
+            candidates.extend(d)
         except UnknownLanguage:
             pass
 
     # total read bytes of the provided text
-    read_bytes_total = sum(c.read_bytes for c in candidates)
+    text_length_total = sum(c.text_length for c in candidates)
 
     # only use candidates that are supported by argostranslate
     candidate_langs = list(
-        filter(lambda l: l.read_bytes != 0 and l.code in __lang_codes, candidates)
+        filter(lambda l: l.text_length != 0 and l.code in __lang_codes, candidates)
     )
 
     # this happens if no language could be detected
@@ -50,7 +53,7 @@ def detect_languages(text):
                 # if more than one is present, calculate the average confidence
                 lang = lc[0]
                 lang.confidence = sum(l.confidence for l in lc) / len(lc)
-                lang.read_bytes = sum(l.read_bytes for l in lc)
+                lang.text_length = sum(l.text_length for l in lc)
                 temp_average_list.append(lang)
             elif lc:
                 # otherwise just add it to the temporary list
@@ -62,7 +65,7 @@ def detect_languages(text):
 
     # sort the candidates descending based on the detected confidence
     candidate_langs.sort(
-        key=lambda l: (l.confidence * l.read_bytes) / read_bytes_total, reverse=True
+        key=lambda l: (l.confidence * l.text_length) / text_length_total, reverse=True
     )
 
     return [{"confidence": l.confidence, "language": l.code} for l in candidate_langs]