Add requests to MathML 2 SVG service to generate SVGs on Publish.

cnxpublishing/db.py

@@ -16,14 +16,17 @@
 import cnxepub
 import psycopg2
 import jinja2
+import requests
 from cnxarchive.utils import (
     IdentHashSyntaxError,
     join_ident_hash, split_ident_hash,
     )
 from cnxepub import ATTRIBUTED_ROLE_KEYS
+from lxml import etree
 from openstax_accounts.interfaces import IOpenstaxAccounts
 from psycopg2.extras import register_uuid
 from pyramid.security import has_permission
+from pyramid.settings import asbool
 from pyramid.threadlocal import (
     get_current_request, get_current_registry,
     )
@@ -531,6 +534,40 @@ def lookup_document_pointer(ident_hash, cursor):
     return cnxepub.DocumentPointer(ident_hash, metadata)
 
 
+def _inject_mathml_svgs(model):
+    """Inject MathML SVG annotations into the model's content."""
+    settings = get_current_registry().settings
+    is_enabled = asbool(settings.get('mathml2svg.enabled?', False))
+    url = settings.get('mathml2svg.url')
+
+    # Bailout when svg generation is disabled.
+    if not is_enabled:
+        return
+
+    xml = etree.fromstring(model.content)
+    mathml_namespace = "http://www.w3.org/1998/Math/MathML"
+    mathml_blocks = xml.xpath(
+        '//m:math[not(/m:annotation-xml[@encoding="image/svg+xml"])]',
+        namespaces={'m': mathml_namespace})
+    for mathml_block in mathml_blocks:
+        # Submit the MathML block to the SVG generation service.
+        payload = {'MathML': etree.tostring(mathml_block)}
+        response = requests.post(url, data=payload)
+        # Inject the SVG into the MathML as an annotation
+        # only if the resposne was good, otherwise skip over it.
+        semantic_block = mathml_block.getchildren()[0]
+        if response.status_code == 200:
+            svg = response.text
+            content_type = response.headers['content-type']
+            # Insert the svg into the content
+            annotation = etree.SubElement(
+                semantic_block,
+                '{{{}}}annotation-xml'.format(mathml_namespace))
+            annotation.set('encoding', content_type)
+            annotation.append(etree.fromstring(svg))
+    model.content = etree.tostring(xml)
+
+
 def add_pending_model_content(cursor, publication_id, model):
     """Updates the pending model's content.
     This is a secondary step not in ``add_pending_model, because
@@ -582,6 +619,9 @@ def mark_invalid_reference(reference):
                     mark_invalid_reference(reference)
             # else, it's a remote or cnx.org reference ...Do nothing.
 
+        # Generate SVGs for MathML
+        _inject_mathml_svgs(model)
+
         args = (psycopg2.Binary(model.content.encode('utf-8')),
                 publication_id, model.id,)
         stmt = """\

cnxpublishing/tests/test_db.py

@@ -22,6 +22,7 @@
 from cnxarchive import config as archive_config
 from cnxarchive.database import initdb as archive_initdb
 from cnxarchive.utils import join_ident_hash, split_ident_hash
+from lxml import etree
 from pyramid import testing
 
 from . import use_cases
@@ -1137,6 +1138,78 @@ def test_add_pending_document_w_invalid_references(self, cursor):
         self.assertEqual(len(state_messages), 2)
         self.assertEqual(state_messages[-1], expected_state_message)
 
+    @db_connect
+    def test_add_pending_document_w_mathml(self, cursor):
+        """Add a pending document with mathml that generates SVG."""
+        publication_id = self.make_publication()
+
+        # Insert a valid module for referencing...
+        cursor.execute("""\
+INSERT INTO abstracts (abstract) VALUES ('abstract')
+RETURNING abstractid""")
+        cursor.execute("""\
+INSERT INTO modules
+(module_ident, portal_type, name,
+ created, revised, abstractid, licenseid,
+ doctype, submitter, submitlog, stateid, parent, parentauthors,
+ language, authors, maintainers, licensors,
+ google_analytics, buylink)
+VALUES
+(1, 'Module', 'mathml module',
+ DEFAULT, DEFAULT, 1, 1,
+ 0, 'admin', 'log', NULL, NULL, NULL,
+ 'en', '{admin}', NULL, '{admin}',
+ DEFAULT, DEFAULT) RETURNING uuid || '@' || major_version""")
+        doc_ident_hash = cursor.fetchone()[0]
+
+        # Create and add a document for the publication.
+        metadata = {
+            'title': 'Document Title',
+            'summary': 'Document Summary',
+            'authors': [{u'id': u'able', u'type': u'cnx-id'}],
+            'publishers': [{'id': 'able', 'type': 'cnx-id'}],
+            'license_url': VALID_LICENSE_URL,
+            }
+        content = """\
+<div class="equation">
+<math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow> <mi>x</mi> <mo>=</mo> <mfrac> <mrow> <mo>&#8722;<!-- &#8722; --></mo> <mi>b</mi> <mo>&#177;<!-- &#177; --></mo> <msqrt> <msup> <mi>b</mi> <mn>2</mn> </msup> <mo>&#8722;<!-- &#8722; --></mo> <mn>4</mn> <mi>a</mi> <mi>c</mi> </msqrt> </mrow> <mrow> <mn>2</mn> <mi>a</mi> </mrow> </mfrac> </mrow></semantics></math>
+</div>"""
+        document = self.make_document(content=content, metadata=metadata)
+
+        # Here we are testing the function of add_pending_document.
+        from ..db import add_pending_model, add_pending_model_content
+        document_ident_hash = add_pending_model(
+            cursor, publication_id, document)
+        from pyramid.threadlocal import get_current_registry
+
+        # Enable the mathml2svg service for this test.
+        get_current_registry().settings['mathml2svg.enabled?'] = 'on'
+
+        with mock.patch('requests.post') as post:
+            post.return_value.status_code = 200
+            post.return_value.headers = {'content-type': 'image/svg+xml'}
+            post.return_value.text = '<svg>mocked</svg>'
+            add_pending_model_content(cursor, publication_id, document)
+
+        # The communication to the mathml2svg service is mocked to return
+        # a stub svg element.
+
+        # This doesn't seem like much, but we only need to check that
+        # the entry was added and the SVG annotation exists.
+        cursor.execute("""
+SELECT convert_from(content, 'utf8')
+FROM pending_documents
+WHERE publication_id = %s""", (publication_id,))
+        persisted_content = cursor.fetchone()[0]
+        self.assertNotEqual(persisted_content, content)
+
+        elms = etree.fromstring(persisted_content)
+        annotation = elms.xpath(
+            '/div/m:math//m:annotation-xml[@encoding="image/svg+xml"]',
+            namespaces={'m': "http://www.w3.org/1998/Math/MathML"})[0]
+        expected = """<annotation-xml xmlns="http://www.w3.org/1998/Math/MathML" encoding="image/svg+xml"><svg>mocked</svg></annotation-xml>"""
+        self.assertEqual(etree.tostring(annotation), expected)
+
     @db_connect
     def test_add_pending_binder_w_document_pointers(self, cursor):
         """Add a pending binder with document pointers."""

development.ini

@@ -21,6 +21,11 @@ db-connection-string = dbname=cnxarchive user=cnxarchive password=cnxarchive
 # size limit of file uploads in MB
 file-upload-limit = 50
 
+# mathml2svg is disabled by default.
+# To enable it use ``mathml2svg.enabled? = yes`` and set the url.
+mathml2svg.url = http://localhost:5689
+mathml2svg.enabled? = no
+
 session_key = 'somkindaseekret'
 # Application API keys with authentication information.
 # This information is organized in the following form:

setup.py

@@ -14,6 +14,7 @@
     'pyramid>=1.5',
     'pyramid_jinja2',
     'pyramid_multiauth',
+    'requests',
     )
 tests_require = [
     'webtest',

testing.ini

@@ -29,6 +29,9 @@ openstax_accounts.login_path = /login
 openstax_accounts.callback_path = /callback
 openstax_accounts.logout_path = /logout
 
+mathml2svg.url = http://localhost:5689
+mathml2svg.enabled? = no
+
 [server:main]
 use = egg:waitress#main
 host = 0.0.0.0