[FEATURE] Added a RESTful URL : /api/corpus/95/ngrams/metadata

gargantext_web/api.py

-from django.http import HttpResponseNotFound, HttpResponse, HttpResponseBadRequest
+from django.http import HttpResponseNotFound, HttpResponse, Http404
+from django.core.exceptions import PermissionDenied, SuspiciousOperation
+from django.core.exceptions import ValidationError
 
 from django.db.models import Avg, Max, Min, Count
 from node.models import NodeType, Node, Ngram
 
+from django.db import connection
+
 # from node.models import Language, ResourceType, Resource
 # from node.models import Node, NodeType, Node_Resource, Project, Corpus
 # from node.admin import CorpusForm, ProjectForm, ResourceForm
@@ -14,23 +18,26 @@ def JsonHttpResponse(data, status=200):
         content_type = "application/json",
         status       = status
     )
+Http400 = SuspiciousOperation
+Http403 = PermissionDenied
 
 _ngrams_order_columns = {
     "frequency" : "-count",
     "alphabetical" : "terms"
 }
 
-def ngrams(request, corpus_id):
+
+def corpus_ngrams(request, corpus_id):
     # parameters retrieval and control
     corpusQuery = Node.objects.filter(id = corpus_id)
     if not corpusQuery:
-        return HttpResponseNotFound("No such corpus.")
+        raise Http404("No such corpus.")
     corpus = corpusQuery.first()
     if corpus.type.name != 'Corpus':
-        return HttpResponseNotFound("No such corpus.")
+        raise Http404("No such corpus.")
     order = request.GET.get('order', 'frequency')
     if order not in _ngrams_order_columns:
-        return HttpResponseBadRequest('The order parameter should take one of the following values: ' +  ', '.join(_ngrams_order_columns))
+        raise ValidationError('The order parameter should take one of the following values: ' +  ', '.join(_ngrams_order_columns), 400)
     order_column = _ngrams_order_columns[order]
     # query building
     ngramsQuery = Ngram.objects.filter(
@@ -46,4 +53,32 @@ def ngrams(request, corpus_id):
     # response building
     return JsonHttpResponse({
         "list" : [ngram.terms for ngram in ngramsQuery],
+    })
+
+def corpus_metadata(request, corpus_id):
+    # parameters retrieval and control
+    corpusQuery = Node.objects.filter(id = corpus_id)
+    if not corpusQuery:
+        raise Http404("No such corpus.")
+    corpus = corpusQuery.first()
+    if corpus.type.name != 'Corpus':
+        raise Http404("No such corpus.")
+    # query building
+    cursor = connection.cursor()
+    cursor.execute(
+    ''' SELECT
+            key,
+            COUNT(*) AS count
+        FROM (
+            SELECT skeys(metadata) AS key
+            FROM %s
+        ) AS keys
+        GROUP BY 
+            key
+        ORDER BY
+            count DESC
+    ''' % (Node._meta.db_table, ))
+    # response building
+    return JsonHttpResponse({
+        "list" : [row[0] for row in cursor.fetchall()],
     })
\ No newline at end of file

gargantext_web/urls.py

@@ -40,7 +40,8 @@ urlpatterns = patterns('',
     url(r'^chart/corpus/(\d+)/data.csv$', send_csv),
     url(r'^graph.json$', send_graph),
 
-    url(r'^api/corpus/(\d+)/ngrams$', gargantext_web.api.ngrams),
+    url(r'^api/corpus/(\d+)/ngrams$', gargantext_web.api.corpus_ngrams),
+    url(r'^api/corpus/(\d+)/metadata$', gargantext_web.api.corpus_metadata),
 )
 
 from django.conf import settings