From 8ffe4bc1453660c1f211496074ebcc68c924327e Mon Sep 17 00:00:00 2001
From: Andrew Godwin
Date: Mon, 12 Dec 2022 07:22:11 -0700
Subject: A better way of handling URIs between local/remote

---
 activities/models/post_attachment.py      | 18 ++++++++--------
 core/uris.py                              | 34 +++++++++++++++++++++++++++++++
 templates/activities/_identity.html       |  2 +-
 templates/activities/_image_uploaded.html |  2 +-
 templates/activities/_mini_post.html      |  2 +-
 templates/activities/_post.html           |  6 +++---
 templates/activities/follows.html         |  2 +-
 templates/base.html                       |  2 +-
 templates/identity/select.html            |  2 +-
 templates/identity/view.html              |  4 ++--
 users/models/identity.py                  | 28 +++++++++++++------------
 11 files changed, 69 insertions(+), 33 deletions(-)
 create mode 100644 core/uris.py

diff --git a/activities/models/post_attachment.py b/activities/models/post_attachment.py
index 7b1ad6b..3b1f425 100644
--- a/activities/models/post_attachment.py
+++ b/activities/models/post_attachment.py
@@ -1,9 +1,9 @@
 from functools import partial
 
-from django.conf import settings
 from django.db import models
 
 from core.uploads import upload_namer
+from core.uris import AutoAbsoluteUrl, RelativeAbsoluteUrl
 from stator.models import State, StateField, StateGraph, StatorModel
 
 
@@ -72,19 +72,19 @@ class PostAttachment(StatorModel):
             "image/webp",
         ]
 
-    def thumbnail_url(self):
+    def thumbnail_url(self) -> RelativeAbsoluteUrl:
         if self.thumbnail:
-            return self.thumbnail.url
+            return RelativeAbsoluteUrl(self.thumbnail.url)
         elif self.file:
-            return self.file.url
+            return RelativeAbsoluteUrl(self.file.url)
         else:
-            return f"https://{settings.MAIN_DOMAIN}/proxy/post_attachment/{self.pk}/"
+            return AutoAbsoluteUrl(f"/proxy/post_attachment/{self.pk}/")
 
     def full_url(self):
         if self.file:
-            return self.file.url
+            return RelativeAbsoluteUrl(self.file.url)
         else:
-            return f"https://{settings.MAIN_DOMAIN}/proxy/post_attachment/{self.pk}/"
+            return AutoAbsoluteUrl(f"/proxy/post_attachment/{self.pk}/")
 
     ### ActivityPub ###
 
@@ -105,8 +105,8 @@ class PostAttachment(StatorModel):
         return {
             "id": self.pk,
             "type": "image" if self.is_image() else "unknown",
-            "url": self.full_url(),
-            "preview_url": self.thumbnail_url(),
+            "url": self.full_url().absolute,
+            "preview_url": self.thumbnail_url().absolute,
             "remote_url": None,
             "meta": {
                 "original": {
diff --git a/core/uris.py b/core/uris.py
new file mode 100644
index 0000000..9ed2a32
--- /dev/null
+++ b/core/uris.py
@@ -0,0 +1,34 @@
+from urllib.parse import urljoin
+
+from django.conf import settings
+
+
+class RelativeAbsoluteUrl:
+    """
+    Represents a URL that can have both "relative" and "absolute" forms
+    for various use either locally or remotely.
+    """
+
+    absolute: str
+    relative: str
+
+    def __init__(self, absolute: str, relative: str | None = None):
+        if "://" not in absolute:
+            raise ValueError(f"Absolute URL {absolute!r} is not absolute!")
+        self.absolute = absolute
+        self.relative = relative or absolute
+
+
+class AutoAbsoluteUrl(RelativeAbsoluteUrl):
+    """
+    Automatically makes the absolute variant by using either settings.MAIN_DOMAIN
+    or a passed identity's URI domain.
+    """
+
+    def __init__(self, relative: str, identity=None):
+        self.relative = relative
+        if identity:
+            absolute_prefix = f"https://{identity.domain.uri_domain}/"
+        else:
+            absolute_prefix = f"https://{settings.MAIN_DOMAIN}/"
+        self.absolute = urljoin(absolute_prefix, self.relative)
diff --git a/templates/activities/_identity.html b/templates/activities/_identity.html
index c48a645..feb3178 100644
--- a/templates/activities/_identity.html
+++ b/templates/activities/_identity.html
@@ -2,7 +2,7 @@
 <div class="post user">
 
     <a href="{{ identity.urls.view }}">
-        <img src="{{ identity.local_icon_url }}" class="icon" alt="Avatar for {{ identity.name_or_handle }}">
+        <img src="{{ identity.local_icon_url.relative }}" class="icon" alt="Avatar for {{ identity.name_or_handle }}">
     </a>
 
     {% if created %}
diff --git a/templates/activities/_image_uploaded.html b/templates/activities/_image_uploaded.html
index 6821328..36bd7fe 100644
--- a/templates/activities/_image_uploaded.html
+++ b/templates/activities/_image_uploaded.html
@@ -1,6 +1,6 @@
 <div class="uploaded-image">
     <input type="hidden" name="attachment" value="{{ attachment.pk }}">
-    <img src="{{ attachment.thumbnail_url }}">
+    <img src="{{ attachment.thumbnail_url.relative }}">
     <p>
         {{ attachment.name|default:"(no description)" }}
     </p>
diff --git a/templates/activities/_mini_post.html b/templates/activities/_mini_post.html
index 19fad76..9f83333 100644
--- a/templates/activities/_mini_post.html
+++ b/templates/activities/_mini_post.html
@@ -3,7 +3,7 @@
 <div class="post mini" data-takahe-id="{{ post.id }}" role="article">
 
     <a href="{{ post.author.urls.view }}" tabindex="-1">
-        <img src="{{ post.author.local_icon_url }}" class="icon">
+        <img src="{{ post.author.local_icon_url.relative }}" class="icon">
     </a>
 
     <a href="{{ post.author.urls.view }}" class="handle">
diff --git a/templates/activities/_post.html b/templates/activities/_post.html
index 099a35f..5802acd 100644
--- a/templates/activities/_post.html
+++ b/templates/activities/_post.html
@@ -3,7 +3,7 @@
 <div class="post {% if reply %}reply{% endif %}" data-takahe-id="{{ post.id }}" role="article" tabindex="0">
 
     <a href="{{ post.author.urls.view }}" tabindex="-1">
-        <img src="{{ post.author.local_icon_url }}" class="icon">
+        <img src="{{ post.author.local_icon_url.relative }}" class="icon">
     </a>
 
     <time _="on click go url {% if link_original %}{{ post.url }}{% else %}{{ post.urls.view }}{% endif %} then halt">
@@ -75,8 +75,8 @@
           <div class="attachments">
             {% for attachment in post.attachments.all %}
               {% if attachment.is_image %}
-                <a href="{{ attachment.full_url }}" class="image">
-                  <img src="{{ attachment.thumbnail_url }}" title="{{ attachment.name }}" alt="{{ attachment.name }}" />
+                <a href="{{ attachment.full_url.relative }}" class="image">
+                  <img src="{{ attachment.thumbnail_url.relative }}" title="{{ attachment.name }}" alt="{{ attachment.name }}" />
                 </a>
               {% endif %}
             {% endfor %}
diff --git a/templates/activities/follows.html b/templates/activities/follows.html
index 6116dd6..27a13d3 100644
--- a/templates/activities/follows.html
+++ b/templates/activities/follows.html
@@ -6,7 +6,7 @@
     <section class="icon-menu">
         {% for identity, details in identities %}
             <a class="option" href="{{ identity.urls.view }}">
-                <img src="{{ identity.local_icon_url }}">
+                <img src="{{ identity.local_icon_url.relative }}">
                 <span class="handle">
                     {{ identity.name_or_handle }}
                     <small>@{{ identity.handle }}</small>
diff --git a/templates/base.html b/templates/base.html
index df8ebdf..4614223 100644
--- a/templates/base.html
+++ b/templates/base.html
@@ -48,7 +48,7 @@
                             <img src="{% static "img/unknown-icon-128.png" %}" title="No identity selected">
                         {% else %}
                             {{ request.identity.username }}
-                            <img src="{{ request.identity.local_icon_url }}" title="{{ request.identity.handle }}">
+                            <img src="{{ request.identity.local_icon_url.relative }}" title="{{ request.identity.handle }}">
                         {% endif %}
                     </a>
                 {% else %}
diff --git a/templates/identity/select.html b/templates/identity/select.html
index d63f886..b3fc41d 100644
--- a/templates/identity/select.html
+++ b/templates/identity/select.html
@@ -6,7 +6,7 @@
     <section class="icon-menu">
         {% for identity in identities %}
             <a class="option" href="{{ identity.urls.activate }}">
-                <img src="{{ identity.local_icon_url }}">
+                <img src="{{ identity.local_icon_url.relative }}">
                 <span class="handle">
                     {{ identity.name_or_handle }}
                     <small>@{{ identity.handle }}</small>
diff --git a/templates/identity/view.html b/templates/identity/view.html
index 612e3d2..8d5806f 100644
--- a/templates/identity/view.html
+++ b/templates/identity/view.html
@@ -13,10 +13,10 @@
 {% block content %}
     <h1 class="identity">
         {% if identity.local_image_url %}
-            <img src="{{ identity.local_image_url }}" class="banner">
+            <img src="{{ identity.local_image_url.relative }}" class="banner">
         {% endif %}
 
-        <img src="{{ identity.local_icon_url }}" class="icon">
+        <img src="{{ identity.local_icon_url.relative }}" class="icon">
 
         {% if request.identity %}
             {% if identity == request.identity %}
diff --git a/users/models/identity.py b/users/models/identity.py
index a8937c9..1ece0fd 100644
--- a/users/models/identity.py
+++ b/users/models/identity.py
@@ -5,7 +5,6 @@ from urllib.parse import urlparse
 import httpx
 import urlman
 from asgiref.sync import async_to_sync, sync_to_async
-from django.conf import settings
 from django.db import IntegrityError, models
 from django.template.defaultfilters import linebreaks_filter
 from django.templatetags.static import static
@@ -18,6 +17,7 @@ from core.ld import canonicalise, format_ld_date, get_list, media_type_from_file
 from core.models import Config
 from core.signatures import HttpSignature, RsaKeys
 from core.uploads import upload_namer
+from core.uris import AutoAbsoluteUrl, RelativeAbsoluteUrl
 from stator.models import State, StateField, StateGraph, StatorModel
 from users.models.domain import Domain
 from users.models.system_actor import SystemActor
@@ -147,25 +147,26 @@ class Identity(StatorModel):
         else:
             return self.profile_uri
 
-    def local_icon_url(self):
+    def local_icon_url(self) -> RelativeAbsoluteUrl:
         """
-        Returns an icon for us, with fallbacks to a placeholder
+        Returns an icon for use by us, with fallbacks to a placeholder
         """
         if self.icon:
-            return self.icon.url
+            return RelativeAbsoluteUrl(self.icon.url)
         elif self.icon_uri:
-            return f"https://{settings.MAIN_DOMAIN}/proxy/identity_icon/{self.pk}/"
+            return AutoAbsoluteUrl(f"/proxy/identity_icon/{self.pk}/")
         else:
-            return static("img/unknown-icon-128.png")
+            return RelativeAbsoluteUrl(static("img/unknown-icon-128.png"))
 
-    def local_image_url(self):
+    def local_image_url(self) -> RelativeAbsoluteUrl | None:
         """
         Returns a background image for us, returning None if there isn't one
         """
         if self.image:
-            return self.image.url
+            return RelativeAbsoluteUrl(self.image.url)
         elif self.image_uri:
-            return f"https://{settings.MAIN_DOMAIN}/proxy/identity_image/{self.pk}/"
+            return AutoAbsoluteUrl(f"/proxy/identity_image/{self.pk}/")
+        return None
 
     @property
     def safe_summary(self):
@@ -470,6 +471,7 @@ class Identity(StatorModel):
     ### Mastodon Client API ###
 
     def to_mastodon_json(self):
+        header_image = self.local_image_url()
         return {
             "id": self.pk,
             "username": self.username,
@@ -477,10 +479,10 @@ class Identity(StatorModel):
             "url": self.absolute_profile_uri(),
             "display_name": self.name,
             "note": self.summary or "",
-            "avatar": self.local_icon_url(),
-            "avatar_static": self.local_icon_url(),
-            "header": self.local_image_url() or "",
-            "header_static": self.local_image_url() or "",
+            "avatar": self.local_icon_url().absolute,
+            "avatar_static": self.local_icon_url().absolute,
+            "header": header_image.absolute if header_image else None,
+            "header_static": header_image.absolute if header_image else None,
             "locked": False,
             "fields": (
                 [
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