Add support for serving users' avatars through the Libravatar API

Pipfile

@@ -47,6 +47,7 @@ django-cors-headers = "*"
 pytest-django = "*"
 "argon2-cffi" = "*"
 python-baseconv = "*"
+django-computed-property = "*"
 
 
 [dev-packages]

Pipfile.lock

@@ -1,7 +1,7 @@
 {
     "_meta": {
         "hash": {
-            "sha256": "a824f0af4df1d0088d5dd66db92329358a5cf0095c71f1cb59f6e60583b912f5"
+            "sha256": "0b68c7a2821e8063bc9d7bae759a9d8dd57785e341e6d23d6421ad93310c7d1b"
         },
         "host-environment-markers": {
             "implementation_name": "cpython",
@@ -11,7 +11,7 @@
             "platform_python_implementation": "CPython",
             "platform_release": "17.5.0",
             "platform_system": "Darwin",
-            "platform_version": "Darwin Kernel Version 17.5.0: Mon Mar  5 22:58:50 PST 2018; root:xnu-4570.51.1~2/RELEASE_X86_64",
+            "platform_version": "Darwin Kernel Version 17.5.0: Tue Mar 13 20:39:15 PDT 2018; root:xnu-4570.51.1~36/RELEASE_X86_64",
             "python_full_version": "3.6.4",
             "python_version": "3.6",
             "sys_platform": "darwin"
@@ -206,6 +206,12 @@
             ],
             "version": "==2.2"
         },
+        "django-computed-property": {
+            "hashes": [
+                "sha256:31aa6453a5c504ce196ba9ae3bacbe0557cadf7ae89e25431b90bf206febd3b3"
+            ],
+            "version": "==0.2.1"
+        },
         "django-cors-headers": {
             "hashes": [
                 "sha256:0e9532628b3aa8806442d4d0b15e56112e6cfbef3735e13401935c98b842a2b4",
@@ -323,36 +329,36 @@
         },
         "lxml": {
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+                "sha256:34d49d0f72dd82b9530322c48b70ac78cca0911275da741c3b1d2f3603c5f295",
-                "sha256:36ffb216e2f361a5a0a7e219aea6cd44da11c64061baed273944aae21223186c",
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-                "sha256:71ac6dac6835de75aaf531cae9ffa447dae0783ba1f43bf6eaccfad3680a5b9c",
+                "sha256:6b6379495d3baacf7ed755ac68547c8dff6ce5d37bf370f0b7678888dc1283f9",
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-                "sha256:2812bc45a7f53f366217b76a1c53e6728fbfa7f7524d16a321ea8f7131428bd1",
+                "sha256:a7182ea298cc3555ea56ffbb0748fe0d5e0d81451e2bc16d7f4645cd01b1ca70",
-                "sha256:124a9d529eec5e10f307eb237df3efc43dd1fb7ebdb5da5e480c4ed372648b6b",
+                "sha256:7f457cbda964257f443bac861d3a36732dcba8183149e7818ee2fb7c86901b94",
-                "sha256:f04b184984c23e0caac3c55eac2fe2dbb88726a5a1b35e23715eff6f29a4705c",
+                "sha256:0c9fef4f8d444e337df96c54544aeb85b7215b2ed7483bb6c35de97ac99f1bcd",
-                "sha256:d06260e6102b2f18dbee3736185cd6a2e1c88c0fad782bf8e9d7a7a1b24e02b0",
+                "sha256:7ff1fc76d8804e0f870c343a72007ff587090c218b0f92d8ee784ac2b6eaf5b9",
-                "sha256:0cddc6cde79e1932efc71d9974a4418184ad0b8ca46c633ad772b2c5eaf36b3c",
+                "sha256:accc9f6b77bed0a6f267b4fae120f6008a951193d548cdbe9b61fc98a08b1cf8",
-                "sha256:9e08918b744b89d30750eca8598f37ae75b16202870db678fde970d85afed3e3",
+                "sha256:bd88c8ce0d1504fdfd96a35911dd4f3edfb2e560d7cfdb5a3d09aa571ae5fbae",
-                "sha256:b46f31e806f6884bd1053ad1d78ecaca6d1bc5dd94a1b783a6ff0bb4b3a60962",
+                "sha256:defabb7fbb99f9f7b3e0b24b286a46855caef4776495211b066e9e6592d12b04",
-                "sha256:dd98d4f88ce0abda2b02c1542d1de22dd342023f3ba09874bd95841283f29433",
+                "sha256:231047b05907315ae9a9b6925751f9fd2c479cf7b100fff62485a25e382ca0d4",
-                "sha256:8f52c4c8f1cf15419193026e731f34a3260a3ce7977b875ba1eb2517b8a3f660",
+                "sha256:0e7996e9b46b4d8b4ac1c329a00e2d10edcd8380b95d2a676fccabf4c1dd0512",
-                "sha256:c18f316cad969111b1ff9e84c82fbc9ae6f25f35701118182d384585940cdf80",
+                "sha256:691f2cd97cf026c611df1ea5055755eec7f878f2d4f4330dc8686583de6fc5fd",
-                "sha256:95b82fdfdaac71640b281da6b9a2c3700177ba5190a786881b184de744ad55de",
+                "sha256:1858b1933d483ec5727549d3fe166eeb54229fbd6a9d3d7ea26d2c8a28048058",
-                "sha256:cef79715f2335bfc1ef7082bcb8b2bac87271431653455221a9127fde146208c",
+                "sha256:0e3cd94c95d30ba9ca3cff40e9b2a14e1a10a4fd8131105b86c6b61648f57e4b",
-                "sha256:4626d699551f66687e5f7e7f9b79bfce611e12edebfb9fec276e2df8ec46541e",
+                "sha256:28f0c6652c1b130f1e576b60532f84b19379485eb8da6185c29bd8c9c9bc97bf",
-                "sha256:cf63f590090404c52f179b7ceacb7cd549de3a1697bcfe2f79be180b2801d109",
+                "sha256:8f37627f16e026523fca326f1b5c9a43534862fede6c3e99c2ba6a776d75c1ab",
-                "sha256:7d96fbb5f23a62300aa9bef7d286cd61aca8902357619c8708c0290aba5df73f"
+                "sha256:e2629cdbcad82b83922a3488937632a4983ecc0fed3e5cfbf430d069382eeb9b"
             ],
-            "version": "==4.2.0"
+            "version": "==4.2.1"
         },
         "markdown": {
             "hashes": [
@@ -373,6 +379,14 @@
             ],
             "version": "==0.5.0"
         },
+        "more-itertools": {
+            "hashes": [
+                "sha256:11a625025954c20145b37ff6309cd54e39ca94f72f6bb9576d1195db6fa2442e",
+                "sha256:0dd8f72eeab0d2c3bd489025bb2f6a1b8342f9b198f6fc37b52d15cfa4531fea",
+                "sha256:c9ce7eccdcb901a2c75d326ea134e0886abfbea5f93e91cc95de9507c0816c44"
+            ],
+            "version": "==4.1.0"
+        },
         "msgpack-python": {
             "hashes": [
                 "sha256:378cc8a6d3545b532dfd149da715abae4fda2a3adb6d74e525d0d5e51f46909b"
@@ -465,10 +479,10 @@
         },
         "py": {
             "hashes": [
-                "sha256:8cca5c229d225f8c1e3085be4fcf306090b00850fefad892f9d96c7b6e2f310f",
+                "sha256:983f77f3331356039fdd792e9220b7b8ee1aa6bd2b25f567a963ff1de5a64f6a",
-                "sha256:ca18943e28235417756316bfada6cd96b23ce60dd532642690dcfdaba988a76d"
+                "sha256:29c9fab495d7528e80ba1e343b958684f4ace687327e6f789a94bf3d1915f881"
             ],
-            "version": "==1.5.2"
+            "version": "==1.5.3"
         },
         "pycparser": {
             "hashes": [
@@ -506,10 +520,10 @@
         },
         "pytest": {
             "hashes": [
-                "sha256:062027955bccbc04d2fcd5d79690947e018ba31abe4c90b2c6721abec734261b",
+                "sha256:6266f87ab64692112e5477eba395cfedda53b1933ccd29478e671e73b420c19c",
-                "sha256:117bad36c1a787e1a8a659df35de53ba05f9f3398fb9e4ac17e80ad5903eb8c5"
+                "sha256:fae491d1874f199537fd5872b5e1f0e74a009b979df9d53d1553fd03da1703e1"
             ],
-            "version": "==3.4.2"
+            "version": "==3.5.0"
         },
         "pytest-django": {
             "hashes": [

lemoncurry/settings/base.py

@@ -72,6 +72,7 @@ INSTALLED_APPS = [
     'analytical',
     'annoying',
     'compressor',
+    'computed_property',
     'corsheaders',
     'debug_toolbar',
     'django_activeurl',

lemoncurry/urls.py

@@ -36,6 +36,7 @@ maps = {'sitemaps': sections}
 urlpatterns = [
     url('', include('home.urls')),
     url('', include('entries.urls')),
+    url('', include('users.urls')),
     url('^.well-known/', include('wellknowns.urls')),
     url('^admin/', otp_admin_site.urls),
     url('^auth/', include('lemonauth.urls')),

users/migrations/0013_auto_20180323_1200.py

@@ -0,0 +1,24 @@
+# Generated by Django 2.0.3 on 2018-03-23 01:00
+
+import computed_property.fields
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('users', '0012_auto_20180129_1614'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='user',
+            name='email_md5',
+            field=computed_property.fields.ComputedCharField(compute_from='calc_email_md5', default='', editable=False, max_length=32, unique=True),
+        ),
+        migrations.AddField(
+            model_name='user',
+            name='email_sha256',
+            field=computed_property.fields.ComputedCharField(compute_from='calc_email_sha256', default='', editable=False, max_length=64, unique=True),
+        ),
+    ]

users/models.py

@@ -1,7 +1,9 @@
+from computed_property import ComputedCharField
 from django.db import models
 from django.contrib.auth.models import AbstractUser, UserManager as DjangoUserManager
 from django.contrib.sites.models import Site as DjangoSite
 from django.utils.functional import cached_property
+from hashlib import md5, sha256
 from meta.models import ModelMeta
 from urllib.parse import urljoin
 from lemoncurry import utils
@@ -46,6 +48,21 @@ class User(ModelMeta, AbstractUser):
     # This is gonna need to change if I ever decide to add multiple-user support ;)
     url = '/'
 
+    email_md5 = ComputedCharField(
+        compute_from='calc_email_md5', max_length=32, unique=True
+    )
+    email_sha256 = ComputedCharField(
+        compute_from='calc_email_sha256', max_length=64, unique=True
+    )
+
+    @property
+    def calc_email_md5(self):
+        return md5(self.email.lower().encode('utf-8')).hexdigest()
+
+    @property
+    def calc_email_sha256(self):
+        return sha256(self.email.lower().encode('utf-8')).hexdigest()
+
     @property
     def name(self):
         return '{0} {1}'.format(self.first_name, self.last_name)

users/urls.py

@@ -0,0 +1,8 @@
+from django.conf.urls import url
+
+from .views import libravatar
+
+app_name = 'users'
+urlpatterns = (
+    url('^avatar/(?P<hash>[a-z0-9]+)$', libravatar, name='libravatar'),
+)

users/views.py

@@ -0,0 +1,49 @@
+from django.http import HttpResponse, HttpResponseRedirect
+from PIL import Image
+
+from lemoncurry import utils
+from .models import User
+
+
+def try_libravatar_org(hash, get):
+    url = 'https://seccdn.libravatar.org/avatar/' + hash
+    if get:
+        url += '?' + get.urlencode()
+    return HttpResponseRedirect(url)
+
+
+def libravatar(request, hash):
+    g = request.GET
+    size = g.get('s', g.get('size', 80))
+    try:
+        size = int(size)
+    except ValueError:
+        return utils.bad_req('size parameter must be an integer')
+    if not 1 <= size <= 128:
+        return utils.bad_req('size parameter must be between 1 and 128')
+
+    if len(hash) == 32:
+        where = {'email_md5': hash}
+    elif len(hash) == 64:
+        where = {'email_sha256': hash}
+    else:
+        return utils.bad_req('hash must be either md5 or sha256')
+
+    # If the user doesn't exist or lacks an avatar, see if libravatar.org has
+    # one for them - libravatar.org falls back to Gravatar when possible (only
+    # for MD5 hashes, since Gravatar doesn't support SHA-256), so this ensures
+    # all the most likely places are checked.
+    try:
+        user = User.objects.get(**where)
+    except User.DoesNotExist:
+        return try_libravatar_org(hash, g)
+
+    if not user.avatar:
+        return try_libravatar_org(hash, g)
+
+    im = Image.open(user.avatar)
+    im_resized = im.resize((size, size))
+
+    response = HttpResponse(content_type='image/'+im.format.lower())
+    im_resized.save(response, im.format)
+    return response