Added html view of serial numbers. Refactored code.

lms/djangoapps/licenses/management/commands/import_serial_numbers.py

@@ -9,15 +9,18 @@ from xmodule.modulestore.django import modulestore
 
 from licenses.models import CourseSoftware, UserLicense
 
+
 class Command(BaseCommand):
     help = """Imports serial numbers for software used in a course.
 
-    Usage: import_serial_numbers <course_id> <software_name> <filename>
+    Usage: import_serial_numbers <course_id> <software_name> <file>
 
-    serial_file is a text file that list one available serial number per line.
+    <file> is a text file that list one available serial number per line.
 
     Example:
-      django-admin.py import_serial_numbers MITx/6.002x/2012_Fall matlab /tmp/matlab-serials.txt
+
+       import_serial_numbers MITx/6.002x/2012_Fall matlab serials.txt
+
     """
     args = "course_id software_id serial_file"
 
@@ -49,7 +52,6 @@ class Command(BaseCommand):
 
         return course_id, software_name, filename
 
-
     def _import_serials(self, software, filename):
         print "Importing serial numbers for {0}.".format(software)
 

lms/djangoapps/licenses/models.py

@@ -1,8 +1,11 @@
-"""
-"""
-from django.db import models
+import logging
+
+from django.db import models, transaction
+
 from student.models import User
 
+log = logging.getLogger("mitx.licenses")
+
 
 class CourseSoftware(models.Model):
     name = models.CharField(max_length=255)
@@ -18,3 +21,58 @@ class UserLicense(models.Model):
     software = models.ForeignKey(CourseSoftware, db_index=True)
     user = models.ForeignKey(User, null=True)
     serial = models.CharField(max_length=255)
+
+
+def get_courses_licenses(user, courses):
+    course_ids = set(course.id for course in courses)
+    all_software = CourseSoftware.objects.filter(course_id__in=course_ids)
+
+    assigned_licenses = UserLicense.objects.filter(software__in=all_software,
+                                                   user=user)
+
+    licenses = dict.fromkeys(all_software, None)
+    for license in assigned_licenses:
+        licenses[license.software] = license
+
+    log.info(assigned_licenses)
+    log.info(licenses)
+
+    return licenses
+
+
+def get_license(user, software):
+    try:
+        license = UserLicense.objects.get(user=user, software=software)
+    except UserLicense.DoesNotExist:
+        license = None
+
+    return license
+
+
+def get_or_create_license(user, software):
+    license = get_license(user, software)
+    if license is None:
+        license = _create_license(user, software)
+
+    return license
+
+
+def _create_license(user, software):
+    license = None
+
+    try:
+        # find one license that has not been assigned, locking the
+        # table/rows with select_for_update to prevent race conditions
+        with transaction.commit_on_success():
+            selected = UserLicense.objects.select_for_update()
+            license = selected.filter(user__isnull=True)[0]
+            license.user = user
+            license.save()
+    except IndexError:
+        # there are no free licenses
+        log.error('No serial numbers available for {0}', software)
+        license = None
+        # TODO [rocha]look if someone has unenrolled from the class
+        # and already has a serial number
+
+    return license

lms/djangoapps/licenses/views.py

@@ -1,60 +1,35 @@
 import logging
-from itertools import groupby
-from collections import Iterable
+from collections import namedtuple, defaultdict
 
-from django.db.models import Q
+from mitxmako.shortcuts import render_to_string
+
+from models import get_courses_licenses, get_or_create_license
 
-from models import CourseSoftware, UserLicense
 
 log = logging.getLogger("mitx.licenses")
 
 
-def get_or_create_courses_licenses(user, courses):
-    user_licenses = get_courses_licenses(user, courses)
+License = namedtuple('License', 'software serial')
 
-    for software, license in user_licenses.iteritems():
+
+def get_licenses_by_course(user, courses):
+    licenses = get_courses_licenses(user, courses)
+    licenses_by_course = defaultdict(list)
+
+    # create missing licenses and group by course_id
+    for software, license in licenses.iteritems():
         if license is None:
-            user_licenses[software] = get_or_create_user_license(user, software)
+            licenses[software] = get_or_create_license(user, software)
 
-    log.info(user_licenses)
+        course_id = software.course_id
+        serial = license.serial if license else None
+        licenses_by_course[course_id].append(License(software, serial))
 
-    return user_licenses
+    # render elements
+    data_by_course = {}
+    for course_id, licenses in licenses_by_course.iteritems():
+        context = {'licenses': licenses}
+        template = 'licenses/serial_numbers.html'
+        data_by_course[course_id] = render_to_string(template, context)
 
-
-def get_courses_licenses(user, courses):
-    course_ids = set(course.id for course in courses)
-    all_software = CourseSoftware.objects.filter(course_id__in=course_ids)
-
-    user_licenses = dict.fromkeys(all_software, None)
-
-    assigned_licenses = UserLicense.objects.filter(software__in=all_software, user=user)
-    assigned_by_software = {lic.software:lic for lic in assigned_licenses}
-
-    for software, license in assigned_by_software.iteritems():
-        user_licenses[software] = license
-
-    return user_licenses
-
-
-def get_or_create_user_license(user, software):
-    license = None
-    try:
-        # Find a licenses associated with the user or with no user
-        # associated.
-        query = (Q(user__isnull=True) | Q(user=user)) & Q(software=software)
-
-        # TODO fix a race condition in this code when more than one
-        # user is getting a license assigned
-
-        license = UserLicense.objects.filter(query)[0]
-
-        if license.user is not user:
-            license.user = user
-            license.save()
-
-    except IndexError:
-        # TODO look if someone has unenrolled from the class and already has a serial number
-        log.error('No serial numbers available for {0}', software)
-
-
-    return license
+    return data_by_course

lms/templates/licenses/serial_numbers.html

@@ -0,0 +1,10 @@
+<dl>
+% for license in licenses:
+  <dt> ${license.software.name}: </dt>
+  % if license.serial:
+    <dd> ${license.serial} </dd>
+  % else:
+    <dd> None Available </dd>
+  % endif
+% endfor
+</dl>