diff --git a/xlit_server.py b/xlit_server.py
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+"""
+Expose Transliteration Engine as an HTTP API.
+
+USAGE:
+```
+from ai4bharat.transliteration import xlit_server
+app, engine = xlit_server.get_app()
+app.run(host='0.0.0.0', port=8000)
+```
+Sample URLs:
+ http://localhost:8000/tl/ta/amma
+ http://localhost:8000/languages
+
+FORMAT:
+ Based on the Varnam API standard
+ https://api.varnamproject.com/tl/hi/bharat
+"""
+
+from flask import Flask, jsonify, request, make_response
+from uuid import uuid4
+from datetime import datetime
+import traceback
+import enum
+
+from .utils import LANG_CODE_TO_DISPLAY_NAME, RTL_LANG_CODES, LANG_CODE_TO_SCRIPT_CODE
+
+class XlitError(enum.Enum):
+ lang_err = "Unsupported langauge ID requested ;( Please check available languages."
+ string_err = "String passed is incompatable ;("
+ internal_err = "Internal crash ;("
+ unknown_err = "Unknown Failure"
+ loading_err = "Loading failed ;( Check if metadata/paths are correctly configured."
+
+app = Flask(__name__)
+app.config['JSON_AS_ASCII'] = False
+
+## ----------------------------- Xlit Engine -------------------------------- ##
+
+from .xlit_src import XlitEngine
+
+MAX_SUGGESTIONS = 8
+DEFAULT_NUM_SUGGESTIONS = 5
+
+ENGINE = {
+ "en2indic": XlitEngine(beam_width=MAX_SUGGESTIONS, rescore=True, model_type="transformer", src_script_type = "roman"),
+ "indic2en": XlitEngine(beam_width=MAX_SUGGESTIONS, rescore=True, model_type="transformer", src_script_type = "indic"),
+}
+
+EXPOSED_LANGS = [
+ {
+ "LangCode": lang_code, # ISO-639 code
+ "Identifier": lang_code, # ISO-639 code
+ "DisplayName": LANG_CODE_TO_DISPLAY_NAME[lang_code],
+ "Author": "AI4Bharat", # Name of developer / team
+ "CompiledDate": "09-April-2022", # date on which model was trained
+ "IsStable": True, # Set `False` if the model is experimental
+ "Direction": "rtl" if lang_code in RTL_LANG_CODES else "ltr",
+ "ScriptCode": LANG_CODE_TO_SCRIPT_CODE[lang_code],
+ } for lang_code in sorted(ENGINE["en2indic"].all_supported_langs)
+]
+
+def get_app():
+ return app, ENGINE
+
+## ---------------------------- API End-points ------------------------------ ##
+
+@app.route('/languages', methods = ['GET', 'POST'])
+def supported_languages():
+ # Format - https://xlit-api.ai4bharat.org/languages
+ response = make_response(jsonify(EXPOSED_LANGS))
+ if 'xlit_user_id' not in request.cookies:
+ # host = request.environ['HTTP_ORIGIN'].split('://')[1]
+ host = '.ai4bharat.org'
+ response.set_cookie('xlit_user_id', uuid4().hex, max_age=365*24*60*60, domain=host, samesite='None', secure=True, httponly=True)
+ return response
+
+@app.route('/tl/<lang_code>/<eng_word>', methods = ['GET', 'POST'])
+def xlit_api(lang_code, eng_word):
+ # Format: https://xlit-api.ai4bharat.org/tl/ta/bharat
+ response = {
+ 'success': False,
+ 'error': '',
+ 'at': str(datetime.utcnow()) + ' +0000 UTC',
+ 'input': eng_word.strip(),
+ 'result': ''
+ }
+
+ transliterate_numerals = request.args.get('transliterate_numerals', default=False, type=lambda v: v.lower() == 'true')
+ num_suggestions = request.args.get('num_suggestions', default=DEFAULT_NUM_SUGGESTIONS, type=int)
+
+ if lang_code not in ENGINE["en2indic"].all_supported_langs:
+ response['error'] = 'Invalid scheme identifier. Supported languages are: '+ str(ENGINE["en2indic"].all_supported_langs)
+ return jsonify(response)
+
+ try:
+ ## Limit char count to --> 70
+ xlit_result = ENGINE["en2indic"].translit_word(eng_word[:70], lang_code, topk=num_suggestions, transliterate_numerals=transliterate_numerals)
+ except Exception as e:
+ xlit_result = XlitError.internal_err
+
+
+ if isinstance(xlit_result, XlitError):
+ response['error'] = xlit_result.value
+ print("XlitError:", traceback.format_exc())
+ else:
+ response['result'] = xlit_result
+ response['success'] = True
+
+ return jsonify(response)
+
+@app.route('/rtl/<lang_code>/<word>', methods = ['GET', 'POST'])
+def reverse_xlit_api(lang_code, word):
+ # Format: https://api.varnamproject.com/rtl/hi/%E0%A4%AD%E0%A4%BE%E0%A4%B0%E0%A4%A4
+ response = {
+ 'success': False,
+ 'error': '',
+ 'at': str(datetime.utcnow()) + ' +0000 UTC',
+ 'input': word.strip(),
+ 'result': ''
+ }
+
+ if lang_code not in ENGINE["indic2en"].all_supported_langs:
+ response['error'] = 'Invalid scheme identifier. Supported languages are: '+ str(ENGINE["indic2en"].all_supported_langs)
+ return jsonify(response)
+
+ num_suggestions = request.args.get('num_suggestions', default=DEFAULT_NUM_SUGGESTIONS, type=int)
+
+ try:
+ ## Limit char count to --> 70
+ xlit_result = ENGINE["indic2en"].translit_word(word[:70], lang_code, topk=num_suggestions)
+ except Exception as e:
+ xlit_result = XlitError.internal_err
+
+ if isinstance(xlit_result, XlitError):
+ response['error'] = xlit_result.value
+ print("XlitError:", traceback.format_exc())
+ else:
+ response['result'] = xlit_result
+ response['success'] = True
+
+ return jsonify(response)
+
+@app.route('/transliterate', methods=['POST'])
+def ulca_api():
+ '''
+ ULCA-compliant endpoint. See for sample request-response:
+ https://github.com/ULCA-IN/ulca/tree/master/specs/examples/model/transliteration-model
+ '''
+ data = request.get_json(force=True)
+
+ if "input" not in data or "config" not in data:
+ return jsonify({
+ "status": {
+ "statusCode": 400,
+ "message": "Ensure `input` and `config` fields missing."
+ }
+ }), 400
+
+ if (data["config"]["language"]["sourceLanguage"] == "en" and data["config"]["language"]["targetLanguage"] in ENGINE["en2indic"].all_supported_langs) or (data["config"]["language"]["sourceLanguage"] in ENGINE["indic2en"].all_supported_langs and data["config"]["language"]["targetLanguage"] == 'en'):
+ pass
+ else:
+ return jsonify({
+ "status": {
+ "statusCode": 501,
+ "message": "The mentioned language-pair is not supported yet."
+ }
+ }), 501
+
+ is_sentence = data["config"]["isSentence"] if "isSentence" in data["config"] else False
+ num_suggestions = 1 if is_sentence else (data["config"]["numSuggestions"] if "numSuggestions" in data["config"] else 5)
+
+ if data["config"]["language"]["targetLanguage"] == "en":
+ engine = ENGINE["indic2en"]
+ lang_code = data["config"]["language"]["sourceLanguage"]
+ else:
+ engine = ENGINE["en2indic"]
+ lang_code = data["config"]["language"]["targetLanguage"]
+
+ outputs = []
+ for item in data["input"]:
+ if is_sentence:
+ item["target"] = [engine.translit_sentence(item["source"], lang_code=lang_code)]
+ else:
+ item["source"] = item["source"][:32]
+ item["target"] = engine.translit_word(item["source"], lang_code=lang_code, topk=num_suggestions)
+
+ return {
+ "output": data["input"],
+ # "status": {
+ # "statusCode": 200,
+ # "message" : "success"
+ # }
+ }, 200
+
+@app.route('/romanize', methods=['POST'])
+def romanizeHandler():
+ langCodeLookup = {
+ "as": "as",
+ "bn": "bn",
+ "gom": "gom",
+ "gu": "gu",
+ "hi": "hi",
+ "kn": "kn",
+ "mai": "mai",
+ "ml": "ml",
+ "mni_mtei": "mni",
+ "mr": "mr",
+ "ne": "ne",
+ "or": "or",
+ "pa": "pa",
+ "sd": "sd",
+ "ta": "ta",
+ "te": "te",
+ "ur": "ur"
+ }
+ rtv = dict()
+
+ data = request.get_json(force=True)
+ for key in data:
+ if key in langCodeLookup:
+ langCode = langCodeLookup[key]
+ text = data[key]
+ response = reverse_xlit_api(langCode, text)
+ responseJson = response.get_json()
+ rtv[key] = responseJson['result']
+ return jsonify(rtv)