Refines Bill Fenner's regex based search through documents for references.

Populates RelatedDocument with relations for references for each type draft Document.
Replaces these reference relationships with updated copies on draft submission.

Note to deployer: There is a script to run in patches/fill_in_references.py that does the work of bringing the database up to date. It takes around 10 minutes to complete on a fast development laptop.

fixes bug ietf-tools#1173
 - Legacy-Id: 6622

Author: rjsparks

ietf/doc/utils.py

@@ -6,6 +6,8 @@
 from ietf.utils import markup_txt
 from ietf.doc.models import *
 
+from ietf.utils import draft
+
 def get_state_types(doc):
     res = []
 
@@ -290,3 +292,47 @@ def update_telechat(request, doc, by, new_telechat_date, new_returning_item=None
             e.desc = "Removed telechat returning item indication"
 
     e.save()
+
+def rebuild_reference_relations(doc):
+    if doc.type.slug != 'draft':
+        return None
+
+    if doc.get_state_slug() == 'rfc':
+        filename=os.path.join(settings.RFC_PATH,doc.canonical_name()+".txt")
+    else:
+        filename=os.path.join(settings.INTERNET_DRAFT_PATH,doc.filename_with_rev())
+
+    try:
+       refs = draft.Draft(draft._gettext(filename), filename).get_refs()
+    except IOError as e:
+       return { 'errors': ["%s :%s" %  (e.strerror, filename)] }
+    
+    doc.relateddocument_set.filter(relationship__slug__in=['refnorm','refinfo','refold','refunk']).delete()
+
+    warnings = []
+    errors = []
+    unfound = set()
+    for ( ref, refType ) in refs.iteritems():
+        refdoc = DocAlias.objects.filter( name=ref )
+        count = refdoc.count()
+        if count == 0:
+            unfound.add( "%s" % ref )
+            continue
+        elif count > 1:
+            errors.append("Too many DocAlias objects found for %s"%ref)
+        else:
+            # Don't add references to ourself
+            if doc != refdoc[0].document:
+                RelatedDocument.objects.get_or_create( source=doc, target=refdoc[ 0 ], relationship=DocRelationshipName.objects.get( slug='ref%s' % refType ) )
+    if unfound:
+        warnings.append('There were %d references with no matching DocAlias'%len(unfound))
+
+    ret = {}
+    if errors:
+        ret['errors']=errors 
+    if warnings:
+        ret['warnings']=warnings 
+    if unfound:
+        ret['unfound']=list(unfound) 
+
+    return ret