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Dodanie obsługi błędów.
[redakcja.git] / apps / api / handlers / library_handlers.py
diff --git a/apps/api/handlers/library_handlers.py b/apps/api/handlers/library_handlers.py
old mode 100644 (file)
new mode 100755 (executable)
index 64b95c2..e2d986e
--- a/apps/api/handlers/library_handlers.py
+++ b/apps/api/handlers/library_handlers.py
@@ -1,33 +1,69 @@
 # -*- encoding: utf-8 -*-
 # -*- encoding: utf-8 -*-
+import os.path
 
 
-__author__= "Łukasz Rekucki"
-__date__ = "$2009-09-25 15:49:50$"
-__doc__ = "Module documentation."
+import logging
+log = logging.getLogger('platforma.api.library')
 
 from piston.handler import BaseHandler, AnonymousBaseHandler
 
 from piston.handler import BaseHandler, AnonymousBaseHandler
+from piston.utils import rc
 
 
-import re
 from datetime import date
 
 from django.core.urlresolvers import reverse
 from datetime import date
 
 from django.core.urlresolvers import reverse
-from django.utils import simplejson as json
+from django.db import IntegrityError
 
 import librarian
 import librarian.html
 
 import librarian
 import librarian.html
-from librarian import dcparser
+import difflib
+import wlrepo 
 
 
-from wlrepo import RevisionNotFound, LibraryException, DocumentAlreadyExists
-from explorer.models import PullRequest
+from explorer.models import GalleryForDocument
 
 # internal imports
 import api.forms as forms
 import api.response as response
 
 # internal imports
 import api.forms as forms
 import api.response as response
-from api.utils import validate_form, hglibrary
-from api.models import PartCache
+from api.utils import validate_form, hglibrary, natural_order
+from api.models import PartCache, PullRequest
+
+from pygments import highlight
+from pygments.lexers import DiffLexer
+from pygments.formatters import HtmlFormatter
+
+#
+import settings
+
+
+def is_prq(username):
+    return username.startswith('$prq-')
+
+def prq_for_user(username):
+    try:
+        return PullRequest.objects.get(id=int(username[5:]))
+    except:
+        return None
+
+def check_user(request, user):
+    log.info("user: %r, perm: %r" % (request.user, request.user.get_all_permissions()) )
+    #pull request
+    if is_prq(user):
+        if not request.user.has_perm('api.view_prq'):
+            yield response.AccessDenied().django_response({
+                'reason': 'access-denied',
+                'message': "You don't have enough priviliges to view pull requests."
+            })
+    # other users
+    elif request.user.username != user:
+        if not request.user.has_perm('api.view_other_document'):
+            yield response.AccessDenied().django_response({
+                'reason': 'access-denied',
+                'message': "You don't have enough priviliges to view other people's document."
+            })
+    pass
 
 #
 # Document List Handlers
 #
 
 #
 # Document List Handlers
 #
+# TODO: security check
 class BasicLibraryHandler(AnonymousBaseHandler):
     allowed_methods = ('GET',)
 
 class BasicLibraryHandler(AnonymousBaseHandler):
     allowed_methods = ('GET',)
 
@@ -37,10 +73,11 @@ class BasicLibraryHandler(AnonymousBaseHandler):
         document_list = [{
             'url': reverse('document_view', args=[docid]),
             'name': docid } for docid in lib.documents() ]
         document_list = [{
             'url': reverse('document_view', args=[docid]),
             'name': docid } for docid in lib.documents() ]
-
         return {'documents' : document_list}
         
         return {'documents' : document_list}
         
-
+#
+# This handler controlls the document collection
+#
 class LibraryHandler(BaseHandler):
     allowed_methods = ('GET', 'POST')
     anonymous = BasicLibraryHandler
 class LibraryHandler(BaseHandler):
     allowed_methods = ('GET', 'POST')
     anonymous = BasicLibraryHandler
@@ -51,34 +88,37 @@ class LibraryHandler(BaseHandler):
 
         documents = {}
         
 
         documents = {}
         
-        for docid in lib.documents():
+        for docid in lib.documents():            
             documents[docid] = {
                 'url': reverse('document_view', args=[docid]),
                 'name': docid,
                 'parts': []
             }
 
             documents[docid] = {
                 'url': reverse('document_view', args=[docid]),
                 'name': docid,
                 'parts': []
             }
 
-        related = PartCache.objects.defer('part_id')\
+        parts = PartCache.objects.defer('part_id')\
             .values_list('part_id', 'document_id').distinct()
             .values_list('part_id', 'document_id').distinct()
+       
+        document_tree = dict(documents)
 
 
-        for part, docid in related:
+        for part, docid in parts:
             # this way, we won't display broken links
             if not documents.has_key(part):
             # this way, we won't display broken links
             if not documents.has_key(part):
+                log.info("NOT FOUND: %s", part)
                 continue
 
                 continue
 
-            child = documents[part]
             parent = documents[docid]
             parent = documents[docid]
+            child = documents[part]
+
+            # not top-level anymore
+            document_tree.pop(part)
+            parent['parts'].append(child)
+        
+        for doc in documents.itervalues():
+            doc['parts'].sort(key=natural_order(lambda d: d['name']))
             
             
-            if isinstance(parent, dict): # the parent is top-level
-                documents.pop(part)                
-                parent['parts'].append(child)
-                documents[part] = child['parts']
-            else: # not top-level
-                parent.append(child)
-            
-        return {
-            'documents': [d for d in documents.itervalues() if isinstance(d, dict)]
-        }
+        return {'documents': sorted(document_tree.itervalues(),
+            key=natural_order(lambda d: d['name']) ) }
+
 
     @validate_form(forms.DocumentUploadForm, 'POST')
     @hglibrary
 
     @validate_form(forms.DocumentUploadForm, 'POST')
     @hglibrary
@@ -90,6 +130,9 @@ class LibraryHandler(BaseHandler):
         else:            
             data = request.FILES['ocr_file'].read().decode('utf-8')
 
         else:            
             data = request.FILES['ocr_file'].read().decode('utf-8')
 
+        if data is None:
+            return response.BadRequest().django_response('You must pass ocr_data or ocr_file.')
+
         if form.cleaned_data['generate_dc']:
             data = librarian.wrap_text(data, unicode(date.today()))
 
         if form.cleaned_data['generate_dc']:
             data = librarian.wrap_text(data, unicode(date.today()))
 
@@ -98,17 +141,17 @@ class LibraryHandler(BaseHandler):
         try:
             lock = lib.lock()            
             try:
         try:
             lock = lib.lock()            
             try:
-                print "DOCID", docid                
+                log.info("DOCID %s", docid)
                 doc = lib.document_create(docid)
                 # document created, but no content yet
                 doc = lib.document_create(docid)
                 # document created, but no content yet
-
                 try:
                     doc = doc.quickwrite('xml', data.encode('utf-8'),
                         '$AUTO$ XML data uploaded.', user=request.user.username)
                 except Exception,e:
                 try:
                     doc = doc.quickwrite('xml', data.encode('utf-8'),
                         '$AUTO$ XML data uploaded.', user=request.user.username)
                 except Exception,e:
+                    import traceback
                     # rollback branch creation
                     lib._rollback()
                     # rollback branch creation
                     lib._rollback()
-                    raise LibraryException("Exception occured:" + repr(e))
+                    raise wlrepo.LibraryException(traceback.format_exc())
 
                 url = reverse('document_view', args=[doc.id])
 
 
                 url = reverse('document_view', args=[doc.id])
 
@@ -120,245 +163,312 @@ class LibraryHandler(BaseHandler):
                     url = url )            
             finally:
                 lock.release()
                     url = url )            
             finally:
                 lock.release()
-        except LibraryException, e:
-            return response.InternalError().django_response(\
-                {'exception': repr(e) })                
-        except DocumentAlreadyExists:
+        except wlrepo.LibraryException, e:
+            import traceback
+            return response.InternalError().django_response({
+                "reason": traceback.format_exc()
+            })
+        except wlrepo.DocumentAlreadyExists:
             # Document is already there
             # Document is already there
-            return response.EntityConflict().django_response(\
-                {"reason": "Document %s already exists." % docid})
+            return response.EntityConflict().django_response({
+                "reason": "already-exists",
+                "message": "Document already exists." % docid
+            })
 
 #
 # Document Handlers
 #
 
 #
 # Document Handlers
 #
-class BasicDocumentHandler(AnonymousBaseHandler):
-    allowed_methods = ('GET',)
 
 
+class DiffHandler(BaseHandler):
+    allowed_methods = ('GET',)
+    
     @hglibrary
     def read(self, request, docid, lib):
     @hglibrary
     def read(self, request, docid, lib):
-        try:    
-            doc = lib.document(docid)
-        except RevisionNotFound:
-            return rc.NOT_FOUND
-
-        result = {
-            'name': doc.id,
-            'html_url': reverse('dochtml_view', args=[doc.id,doc.revision]),
-            'text_url': reverse('doctext_view', args=[doc.id,doc.revision]),
-            'dc_url': reverse('docdc_view', args=[doc.id,doc.revision]),
-            'public_revision': doc.revision,
-        }
+        '''Return diff between source_revision and target_revision)'''        
+        revision = request.GET.get('revision')
+        if not revision:
+            return ''
+        source_document = lib.document(docid)
+        target_document = lib.document_for_revision(revision)
+        print source_document, target_document
+        
+        diff = difflib.unified_diff(
+            source_document.data('xml').splitlines(True),
+            target_document.data('xml').splitlines(True),
+            'source',
+            'target')
+        
+        s =  ''.join(list(diff))
+        return highlight(s, DiffLexer(), HtmlFormatter(cssclass="pastie"))
 
 
-        return result
 
 #
 # Document Meta Data
 #
 class DocumentHandler(BaseHandler):
     allowed_methods = ('GET', 'PUT')
 
 #
 # Document Meta Data
 #
 class DocumentHandler(BaseHandler):
     allowed_methods = ('GET', 'PUT')
-    anonymous = BasicDocumentHandler
 
 
+    @validate_form(forms.DocumentRetrieveForm, 'GET')
     @hglibrary
     @hglibrary
-    def read(self, request, docid, lib):
+    def read(self, request, form, docid, lib):
         """Read document's meta data"""       
         """Read document's meta data"""       
-        try:
-            doc = lib.document(docid)
-            udoc = doc.take(request.user.username)
-        except RevisionNotFound:
-            return request.EnityNotFound().django_response()
-
-        # is_shared = udoc.ancestorof(doc)
-        # is_uptodate = is_shared or shared.ancestorof(document)
+        log.info(u"User '%s' wants to edit %s(%s) as %s" % \
+            (request.user.username, docid, form.cleaned_data['revision'], form.cleaned_data['user']) )
 
 
-        result = {
-            'name': udoc.id,
-            'html_url': reverse('dochtml_view', args=[udoc.id,udoc.revision]),
-            'text_url': reverse('doctext_view', args=[udoc.id,udoc.revision]),
-            'dc_url': reverse('docdc_view', args=[udoc.id,udoc.revision]),
-            'user_revision': udoc.revision,
-            'public_revision': doc.revision,            
-        }       
+        user = form.cleaned_data['user'] or request.user.username
+        rev = form.cleaned_data['revision'] or 'latest'
 
 
-        return result
+        for error in check_user(request, user):
+            return error
+            
+        try:
+            doc = lib.document(docid, user, rev=rev)
+        except wlrepo.RevisionMismatch, e:
+            # the document exists, but the revision is bad
+            return response.EntityNotFound().django_response({
+                'reason': 'revision-mismatch',
+                'message': e.message,
+                'docid': docid,
+                'user': user,
+            })
+        except wlrepo.RevisionNotFound, e:
+            # the user doesn't have this document checked out
+            # or some other weird error occured
+            # try to do the checkout
+            try:
+                if user == request.user.username:
+                    mdoc = lib.document(docid)
+                    doc = mdoc.take(user)
+                elif is_prq(user):
+                    prq = prq_for_user(user)
+                    # commiter's document
+                    prq_doc = lib.document_for_revision(prq.source_revision)
+                    doc = prq_doc.take(user)
+                else:
+                    return response.EntityNotFound().django_response({
+                        'reason': 'document-not-found',
+                        'message': e.message,
+                        'docid': docid,
+                        'user': user,
+                    })
+            except wlrepo.RevisionNotFound, e:
+                return response.EntityNotFound().django_response({
+                    'reason': 'document-not-found',
+                    'message': e.message,
+                    'docid': docid,
+                    'user': user
+                })
 
 
-    @hglibrary
-    def update(self, request, docid, lib):
-        """Update information about the document, like display not"""
-        return
+        return {
+            'name': doc.id,
+            'user': user,
+            'html_url': reverse('dochtml_view', args=[doc.id]),
+            'text_url': reverse('doctext_view', args=[doc.id]),
+            # 'dc_url': reverse('docdc_view', args=[doc.id]),
+            'gallery_url': reverse('docgallery_view', args=[doc.id]),
+            'merge_url': reverse('docmerge_view', args=[doc.id]),
+            'revision': doc.revision,
+            'timestamp': doc.revision.timestamp,
+            # 'public_revision': doc.revision,
+            # 'public_timestamp': doc.revision.timestamp,
+        }   
+
+    
+#    @hglibrary
+#    def update(self, request, docid, lib):
+#        """Update information about the document, like display not"""
+#        return
 #
 #
 #
 class DocumentHTMLHandler(BaseHandler):
 #
 #
 #
 class DocumentHTMLHandler(BaseHandler):
-    allowed_methods = ('GET', 'PUT')
+    allowed_methods = ('GET')
 
 
+    @validate_form(forms.DocumentRetrieveForm, 'GET')
     @hglibrary
     @hglibrary
-    def read(self, request, docid, revision, lib):
+    def read(self, request, form, docid, lib, stylesheet='full'):
         """Read document as html text"""
         try:
         """Read document as html text"""
         try:
-            if revision == 'latest':
-                document = lib.document(docid)
-            else:
-                document = lib.document_for_rev(revision)
-
-            return librarian.html.transform(document.data('xml'), is_file=False)
-        except RevisionNotFound:
-            return response.EntityNotFound().django_response()
+            revision = form.cleaned_data['revision']
+            user = form.cleaned_data['user'] or request.user.username
+            document = lib.document_for_revision(revision)
+
+            if document.id != docid:
+                return response.BadRequest().django_response({
+                    'reason': 'name-mismatch',
+                    'message': 'Provided revision is not valid for this document'
+                })
 
 
+            if document.owner != user:
+                return response.BadRequest().django_response({
+                    'reason': 'user-mismatch',
+                    'message': "Provided revision doesn't belong to user %s" % user
+                })
 
 
+            for error in check_user(request, user):
+                return error
 
 
+            return librarian.html.transform(document.data('xml'), is_file=False, \
+                parse_dublincore=False, stylesheet=stylesheet,\
+                options={
+                    "with-paths": 'boolean(1)',                    
+                })
+                
+        except (wlrepo.EntryNotFound, wlrepo.RevisionNotFound), e:
+            return response.EntityNotFound().django_response({
+                'reason': 'not-found', 'message': e.message})
+        except librarian.ValidationError, e:
+            return response.InternalError().django_response({
+                'reason': 'xml-non-valid', 'message': e.message or u''})
+        except librarian.ParseError, e:
+            return response.InternalError().django_response({
+                'reason': 'xml-parse-error', 'message': e.message or u'' })
 
 #
 
 #
-# Document Text View
+# Image Gallery
 #
 
 #
 
-XINCLUDE_REGEXP = r"""<(?:\w+:)?include\s+[^>]*?href=("|')wlrepo://(?P<link>[^\1]+?)\1\s*[^>]*?>"""
-#
-#
-class DocumentTextHandler(BaseHandler):
-    allowed_methods = ('GET', 'PUT')
+class DocumentGalleryHandler(BaseHandler):
+    allowed_methods = ('GET', 'POST')
+    
+    
+    def read(self, request, docid):
+        """Read meta-data about scans for gallery of this document."""
+        galleries = []
+        from urllib import quote
+
+        for assoc in GalleryForDocument.objects.filter(document=docid):
+            dirpath = os.path.join(settings.MEDIA_ROOT, assoc.subpath)
+
+            if not os.path.isdir(dirpath):
+                log.warn(u"[WARNING]: missing gallery %s", dirpath)
+                continue
 
 
-    @hglibrary
-    def read(self, request, docid, revision, lib):
-        """Read document as raw text"""               
-        try:
-            if revision == 'latest':
-                document = lib.document(docid)
-            else:
-                document = lib.document_for_rev(revision)
+            gallery = {'name': assoc.name, 'pages': []}
             
             
-            # TODO: some finer-grained access control
-            return document.data('xml')
-        except RevisionNotFound:
-            return response.EntityNotFound().django_response()
-
-    @hglibrary
-    def update(self, request, docid, revision, lib):
-        try:
-            data = request.PUT['contents']            
-
-            if request.PUT.has_key('message'):
-                msg = u"$USER$ " + request.PUT['message']
-            else:
-                msg = u"$AUTO$ XML content update."
-
-            current = lib.document(docid, request.user.username)
-            orig = lib.document_for_rev(revision)
-
-            if current != orig:
-                return response.EntityConflict().django_response({
-                        "reason": "out-of-date",
-                        "provided_revision": orig.revision,
-                        "latest_revision": current.revision })
-
-            # try to find any Xinclude tags
-            includes = [m.groupdict()['link'] for m in (re.finditer(\
-                XINCLUDE_REGEXP, data, flags=re.UNICODE) or []) ]
-
-            # TODO: provide useful routines to make this simpler
-            def xml_update_action(lib, resolve):
-                try:
-                    f = lib._fileopen(resolve('parts'), 'r')
-                    stored_includes = json.loads(f.read())
-                    f.close()
-                except:
-                    stored_includes = []
+            for file in os.listdir(dirpath):
+                if not isinstance(file, unicode):
+                    try:
+                        file = file.decode('utf-8')
+                    except:
+                        log.warn(u"File %r in gallery %r is not unicode. Ommiting."\
+                            % (file, dirpath) )
+                        file = None
+
+                if file is not None:
+                    name, ext = os.path.splitext(os.path.basename(file))
+
+                    if ext.lower() not in [u'.png', u'.jpeg', u'.jpg']:
+                        log.warn(u"Ignoring: %s %s", name, ext)
+                        url = None
+
+                    url = settings.MEDIA_URL + assoc.subpath + u'/' + file
                 
                 
-                if stored_includes != includes:
-                    f = lib._fileopen(resolve('parts'), 'w+')
-                    f.write(json.dumps(includes))
-                    f.close()
+                if url is None:
+                    url = settings.MEDIA_URL + u'/missing.png'
+                    
+                gallery['pages'].append( quote(url.encode('utf-8')) )
 
 
-                    lib._fileadd(resolve('parts'))
+            gallery['pages'].sort()
+            galleries.append(gallery)
 
 
-                    # update the parts cache
-                    PartCache.update_cache(docid, current.owner,\
-                        stored_includes, includes)
+        return galleries
 
 
-                # now that the parts are ok, write xml
-                f = lib._fileopen(resolve('xml'), 'w+')
-                f.write(data)
-                f.close()
-                
-            ndoc = current.invoke_and_commit(\
-                xml_update_action, lambda d: (msg, current.owner) )
+    def create(self, request, docid):
+        if not request.user.is_superuser:
+            return rc.FORBIDDEN
+        
+        new_path = request.POST.get('path')
+        
+        if new_path:
+            gallery, created = GalleryForDocument.objects.get_or_create(
+                document = docid,
+                defaults = {
+                    'subpath': new_path,
+                }
+            )
 
 
-            try:
-                # return the new revision number
-                return response.SuccessAllOk.django_response({
-                    "document": ndoc.id,
-                    "subview": "xml",
-                    "previous_revision": current.revision,
-                    "updated_revision": ndoc.revision
-                })
-            except Exception, e:
-                if ndoc: lib._rollback()
-                raise e        
-        except RevisionNotFound, e:
-            return response.EntityNotFound().django_response(e)
+            if not created:
+                gallery.subpath = new_path
+                gallery.save()
+
+            return rc.CREATED
+        
+        return rc.BAD_REQUEST
 
 #
 # Dublin Core handlers
 #
 # @requires librarian
 #
 
 #
 # Dublin Core handlers
 #
 # @requires librarian
 #
-class DocumentDublinCoreHandler(BaseHandler):
-    allowed_methods = ('GET', 'PUT')
-
-    @hglibrary
-    def read(self, request, docid, revision, lib):
-        """Read document as raw text"""        
-        try:
-            if revision == 'latest':
-                doc = lib.document(docid)
-            else:
-                doc = lib.document_for_rev(revision)
-            
-            bookinfo = dcparser.BookInfo.from_string(doc.data('xml'))
-            return bookinfo.serialize()
-        except RevisionNotFound:
-            return response.EntityNotFound().django_response()
-
-    @hglibrary
-    def update(self, request, docid, revision, lib):
-        try:
-            bi_json = request.PUT['contents']            
-            if request.PUT.has_key('message'):
-                msg = u"$USER$ " + request.PUT['message']
-            else:
-                msg = u"$AUTO$ Dublin core update."
-
-            current = lib.document(docid, request.user.username)
-            orig = lib.document_for_rev(revision)
-
-            if current != orig:
-                return response.EntityConflict().django_response({
-                        "reason": "out-of-date",
-                        "provided": orig.revision,
-                        "latest": current.revision })
-
-            xmldoc = parser.WLDocument.from_string(current.data('xml'))
-            document.book_info = dcparser.BookInfo.from_json(bi_json)
-
-            # zapisz
-            ndoc = current.quickwrite('xml', \
-                document.serialize().encode('utf-8'),\
-                message=msg, user=request.user.username)
-
-            try:
-                # return the new revision number
-                return {
-                    "document": ndoc.id,
-                    "subview": "dc",
-                    "previous_revision": current.revision,
-                    "updated_revision": ndoc.revision
-                }
-            except Exception, e:
-                lib._rollback()
-                raise e
-        except RevisionNotFound:
-            return response.EntityNotFound().django_response()
-
-
+#class DocumentDublinCoreHandler(BaseHandler):
+#    allowed_methods = ('GET', 'POST')
+#
+#    @hglibrary
+#    def read(self, request, docid, lib):
+#        """Read document as raw text"""
+#        try:
+#            revision = request.GET.get('revision', 'latest')
+#
+#            if revision == 'latest':
+#                doc = lib.document(docid)
+#            else:
+#                doc = lib.document_for_revision(revision)
+#
+#
+#            if document.id != docid:
+#                return response.BadRequest().django_response({'reason': 'name-mismatch',
+#                    'message': 'Provided revision is not valid for this document'})
+#
+#            bookinfo = dcparser.BookInfo.from_string(doc.data('xml'))
+#            return bookinfo.serialize()
+#        except (EntryNotFound, RevisionNotFound), e:
+#            return response.EntityNotFound().django_response({
+#                'exception': type(e), 'message': e.message})
+#
+#    @hglibrary
+#    def create(self, request, docid, lib):
+#        try:
+#            bi_json = request.POST['contents']
+#            revision = request.POST['revision']
+#
+#            if request.POST.has_key('message'):
+#                msg = u"$USER$ " + request.PUT['message']
+#            else:
+#                msg = u"$AUTO$ Dublin core update."
+#
+#            current = lib.document(docid, request.user.username)
+#            orig = lib.document_for_revision(revision)
+#
+#            if current != orig:
+#                return response.EntityConflict().django_response({
+#                        "reason": "out-of-date",
+#                        "provided": orig.revision,
+#                        "latest": current.revision })
+#
+#            xmldoc = parser.WLDocument.from_string(current.data('xml'))
+#            document.book_info = dcparser.BookInfo.from_json(bi_json)
+#
+#            # zapisz
+#            ndoc = current.quickwrite('xml', \
+#                document.serialize().encode('utf-8'),\
+#                message=msg, user=request.user.username)
+#
+#            try:
+#                # return the new revision number
+#                return {
+#                    "document": ndoc.id,
+#                    "subview": "dc",
+#                    "previous_revision": current.revision,
+#                    "revision": ndoc.revision,
+#                    'timestamp': ndoc.revision.timestamp,
+#                    "url": reverse("docdc_view", args=[ndoc.id])
+#                }
+#            except Exception, e:
+#                if ndoc: lib._rollback()
+#                raise e
+#        except RevisionNotFound:
+#            return response.EntityNotFound().django_response()
 
 class MergeHandler(BaseHandler):
     allowed_methods = ('POST',)
 
 class MergeHandler(BaseHandler):
     allowed_methods = ('POST',)
@@ -367,75 +477,125 @@ class MergeHandler(BaseHandler):
     @hglibrary
     def create(self, request, form, docid, lib):
         """Create a new document revision from the information provided by user"""
     @hglibrary
     def create(self, request, form, docid, lib):
         """Create a new document revision from the information provided by user"""
+        try:
+            revision = form.cleaned_data['revision']
 
 
-        target_rev = form.cleaned_data['target_revision']
-
-        doc = lib.document(docid)
-        udoc = doc.take(request.user.username)
+            # fetch the main branch document
+            doc = lib.document(docid)
 
 
-        if target_rev == 'latest':
-            target_rev = udoc.revision
+            # fetch the base document
+            user_doc = lib.document_for_revision(revision)
+            base_doc = user_doc.latest()
 
 
-        if str(udoc.revision) != target_rev:
-            # user think doesn't know he has an old version
-            # of his own branch.
-            
-            # Updating is teorericly ok, but we need would
-            # have to force a refresh. Sharing may be not safe,
-            # 'cause it doesn't always result in update.
-
-            # In other words, we can't lie about the resource's state
-            # So we should just yield and 'out-of-date' conflict
-            # and let the client ask again with updated info.
-
-            # NOTE: this could result in a race condition, when there
-            # are 2 instances of the same user editing the same document.
-            # Instance "A" trying to update, and instance "B" always changing
-            # the document right before "A". The anwser to this problem is
-            # for the "A" to request a merge from 'latest' and then
-            # check the parent revisions in response, if he actually
-            # merge from where he thinks he should. If not, the client SHOULD
-            # update his internal state.
-            return response.EntityConflict().django_response({
+            if base_doc != user_doc:
+                return response.EntityConflict().django_response({
                     "reason": "out-of-date",
                     "reason": "out-of-date",
-                    "provided": target_rev,
-                    "latest": udoc.revision })
-
-        if not request.user.has_perm('explorer.book.can_share'):
-            # User is not permitted to make a merge, right away
-            # So we instead create a pull request in the database
-            prq = PullRequest(
-                comitter=request.user,
-                document=docid,
-                source_revision = str(udoc.revision),
-                status="N",
-                comment = form.cleaned_data['comment'] or '$AUTO$ Document shared.'
-            )
-
-            prq.save()
-            return response.RequestAccepted().django_response(\
-                ticket_status=prq.status, \
-                ticket_uri=reverse("pullrequest_view", args=[prq.id]) )
-
-        if form.cleaned_data['type'] == 'update':
-            # update is always performed from the file branch
-            # to the user branch
-            success, changed = udoc.update(request.user.username)
-
-        if form.cleaned_data['type'] == 'share':
-            success, changed = udoc.share(form.cleaned_data['comment'])
-
-        if not success:
-            return response.EntityConflict().django_response()
-
-        if not changed:
-            return response.SuccessNoContent().django_response()
-
-        new_udoc = udoc.latest()
+                    "provided": str(user_doc.revision),
+                    "latest": str(base_doc.revision)
+                })
 
 
-        return response.SuccessAllOk().django_response({
-            "name": udoc.id,
-            "parent_user_resivion": udoc.revision,
-            "parent_revision": doc.revision,
-            "revision": udoc.revision,
-        })
+            if form.cleaned_data['type'] == 'update':
+                # update is always performed from the file branch
+                # to the user branch
+                user_doc_new = base_doc.update(request.user.username)
+
+                if user_doc_new == user_doc:
+                    return response.SuccessAllOk().django_response({
+                        "result": "no-op"
+                    })
+
+                # shared document is the same
+                doc_new = doc
+
+            if form.cleaned_data['type'] == 'share':
+                if not base_doc.up_to_date():
+                    return response.BadRequest().django_response({
+                        "reason": "not-fast-forward",
+                        "message": "You must first update your branch to the latest version."
+                    })
+
+                anwser, info = base_doc.would_share()
+
+                if not anwser:
+                    return response.SuccessAllOk().django_response({
+                        "result": "no-op", "message": info
+                    })
+
+                # check for unresolved conflicts
+                if base_doc.has_conflict_marks():
+                    return response.BadRequest().django_response({
+                        "reason": "unresolved-conflicts",
+                        "message": "There are unresolved conflicts in your file. Fix them, and try again."
+                    })
+
+                if not request.user.has_perm('api.share_document'):
+                    # User is not permitted to make a merge, right away
+                    # So we instead create a pull request in the database
+                    try:
+                        prq, created = PullRequest.objects.get_or_create(
+                            comitter = request.user,
+                            document = docid,
+                            status = "N",
+                            defaults = {
+                                'source_revision': str(base_doc.revision),
+                                'comment': form.cleaned_data['message'] or '$AUTO$ Document shared.',
+                            }
+                        )
+
+                        # there can't be 2 pending request from same user
+                        # for the same document
+                        if not created:
+                            prq.source_revision = str(base_doc.revision)
+                            prq.comment = prq.comment + 'u\n\n' + (form.cleaned_data['message'] or u'')
+                            prq.save()
+
+                        return response.RequestAccepted().django_response(\
+                            ticket_status=prq.status, \
+                            ticket_uri=reverse("pullrequest_view", args=[prq.id]) )
+                    except IntegrityError:
+                        return response.EntityConflict().django_response({
+                            'reason': 'request-already-exist'
+                        })
+
+                changed = base_doc.share(form.cleaned_data['message'])
+
+                # update shared version if needed
+                if changed:
+                    doc_new = doc.latest()
+                else:
+                    doc_new = doc
+
+                # the user wersion is the same
+                user_doc_new = base_doc
+
+            # The client can compare parent_revision to revision
+            # to see if he needs to update user's view
+            # Same goes for shared view
+
+            return response.SuccessAllOk().django_response({
+                "result": "success",
+                "name": user_doc_new.id,
+                "user": user_doc_new.owner,
+
+                "revision": user_doc_new.revision,
+                'timestamp': user_doc_new.revision.timestamp,
+
+                "parent_revision": user_doc.revision,
+                "parent_timestamp": user_doc.revision.timestamp,
+
+                "shared_revision": doc_new.revision,
+                "shared_timestamp": doc_new.revision.timestamp,
+
+                "shared_parent_revision": doc.revision,
+                "shared_parent_timestamp": doc.revision.timestamp,
+            })
+        except wlrepo.OutdatedException, e:
+            return response.BadRequest().django_response({
+                        "reason": "not-fast-forward",
+                        "message": e.message
+                    })
+        except wlrepo.LibraryException, e:
+            return response.InternalError().django_response({
+                        "reason": "merge-error",
+                        "message": e.message
+                    })