Resolver: refactor (#10813)

Simplify a couple of things, and we can remove the overrides from .com after this.

- _get_canonical_project and _get_canonical_project_data are basically the same, the former tries to recursively resolve the project for cases that we don't really support, and the second just checks for the cases that we do support and returns the relationship in case of a subproject. So I just renamed _get_canonical_project_data to _get_canonical_project.
- We were passing the project slug when resolving the path (this was a residual from where we were allowing `USE_SUBDOMAIN=False`).
- Resolving is now split into two steps: resolving the domain, and resolving the path.
- We were using `require_https` for .com only, this was since on .com we were using the https attribute to track the progress of a custom domain, this is no longer the case, all custom domains on .com are https.
- `_use_custom_domain` is the same as `_use_cname`.
- Two more methods to resolve a path were added, they are basically the same as `resolve`, but they work on the object itself, instead of passing each part separately. This results in fewer queries in case the version object is already in memory.

readthedocs/core/resolver.py

@@ -4,16 +4,15 @@
 import structlog
 from django.conf import settings
 
-from readthedocs.builds.constants import EXTERNAL
-from readthedocs.core.utils.extend import SettingsOverrideObject
+from readthedocs.builds.constants import EXTERNAL, INTERNAL
 from readthedocs.core.utils.url import unsafe_join_url_path
 from readthedocs.subscriptions.constants import TYPE_CNAME
 from readthedocs.subscriptions.products import get_feature
 
 log = structlog.get_logger(__name__)
 
 
-class ResolverBase:
+class Resolver:
 
     """
     Read the Docs URL Resolver.
@@ -56,7 +55,6 @@ class ResolverBase:
 
     def base_resolve_path(
         self,
-        project_slug,
         filename,
         version_slug=None,
         language=None,
@@ -91,7 +89,6 @@ def base_resolve_path(
 
         subproject_alias = project_relationship.alias if project_relationship else ""
         return path.format(
-            project=project_slug,
             filename=filename,
             version=version_slug,
             language=language,
@@ -112,7 +109,7 @@ def resolve_path(
 
         filename = self._fix_filename(filename)
 
-        parent_project, project_relationship = self._get_canonical_project_data(project)
+        parent_project, project_relationship = self._get_canonical_project(project)
         single_version = bool(project.single_version or single_version)
 
         # If the project is a subproject, we use the custom prefix
@@ -125,7 +122,6 @@ def resolve_path(
             custom_prefix = parent_project.custom_prefix
 
         return self.base_resolve_path(
-            project_slug=parent_project.slug,
             filename=filename,
             version_slug=version_slug,
             language=language,
@@ -134,25 +130,94 @@ def resolve_path(
             custom_prefix=custom_prefix,
         )
 
-    def resolve_domain(self, project, use_canonical_domain=True):
+    def resolve_version(self, project, version=None, filename="/"):
+        """
+        Get the URL for a specific version of a project.
+
+        If no version is given, the default version is used.
+
+        Use this instead of ``resolve`` if you have the version object already.
+        """
+        if not version:
+            default_version_slug = project.get_default_version()
+            version = project.versions(manager=INTERNAL).get(slug=default_version_slug)
+
+        domain, use_https = self._get_project_domain(
+            project,
+            external_version_slug=version.slug if version.is_external else None,
+        )
+        path = self.resolve_path(
+            project=project,
+            filename=filename,
+            version_slug=version.slug,
+            language=project.language,
+            single_version=project.single_version,
+        )
+        protocol = "https" if use_https else "http"
+        return urlunparse((protocol, domain, path, "", "", ""))
+
+    def resolve_project(self, project, filename="/"):
+        """
+        Get the URL for a project.
+
+        This is the URL where the project is served from,
+        it doesn't include the version or language.
+
+        Useful to link to a known filename in the project.
+        """
+        domain, use_https = self._get_project_domain(project)
+        protocol = "https" if use_https else "http"
+        return urlunparse((protocol, domain, filename, "", "", ""))
+
+    def _get_project_domain(
+        self, project, external_version_slug=None, use_canonical_domain=True
+    ):
         """
         Get the domain from where the documentation of ``project`` is served from.
 
         :param project: Project object
         :param bool use_canonical_domain: If `True` use its canonical custom domain if available.
+        :returns: Tuple of ``(domain, use_https)``.
         """
-        canonical_project = self._get_canonical_project(project)
-        if use_canonical_domain and self._use_cname(canonical_project):
-            domain = canonical_project.get_canonical_custom_domain()
-            if domain:
-                return domain.domain
+        use_https = settings.PUBLIC_DOMAIN_USES_HTTPS
+        canonical_project, _ = self._get_canonical_project(project)
+        domain = self._get_project_subdomain(canonical_project)
+        if external_version_slug:
+            domain = self._get_external_subdomain(
+                canonical_project, external_version_slug
+            )
+        elif use_canonical_domain and self._use_cname(canonical_project):
+            domain_object = canonical_project.get_canonical_custom_domain()
+            if domain_object:
+                use_https = domain_object.https
+                domain = domain_object.domain
 
-        return self._get_project_subdomain(canonical_project)
+        return domain, use_https
+
+    def get_domain(self, project, use_canonical_domain=True):
+        domain, use_https = self._get_project_domain(
+            project, use_canonical_domain=use_canonical_domain
+        )
+        protocol = "https" if use_https else "http"
+        return urlunparse((protocol, domain, "", "", "", ""))
+
+    def get_domain_without_protocol(self, project, use_canonical_domain=True):
+        """
+        Get the domain from where the documentation of ``project`` is served from.
+
+        This doesn't include the protocol.
+
+        :param project: Project object
+        :param bool use_canonical_domain: If `True` use its canonical custom domain if available.
+        """
+        domain, _ = self._get_project_domain(
+            project, use_canonical_domain=use_canonical_domain
+        )
+        return domain
 
     def resolve(
         self,
         project,
-        require_https=False,
         filename="",
         query_params="",
         external=None,
@@ -165,36 +230,11 @@ def resolve(
         if external is None:
             external = self._is_external(project, version_slug)
 
-        canonical_project = self._get_canonical_project(project)
-        custom_domain = canonical_project.get_canonical_custom_domain()
-        use_custom_domain = self._use_custom_domain(custom_domain)
-
-        if external:
-            domain = self._get_external_subdomain(canonical_project, version_slug)
-        elif use_custom_domain:
-            domain = custom_domain.domain
-        else:
-            domain = self._get_project_subdomain(canonical_project)
-
-        use_https_protocol = any(
-            [
-                # Rely on the ``Domain.https`` field
-                use_custom_domain and custom_domain.https,
-                # or force it if specified
-                require_https,
-                # or fallback to settings
-                settings.PUBLIC_DOMAIN_USES_HTTPS
-                and settings.PUBLIC_DOMAIN
-                and any(
-                    [
-                        settings.PUBLIC_DOMAIN in domain,
-                        settings.RTD_EXTERNAL_VERSION_DOMAIN in domain,
-                    ]
-                ),
-            ]
+        domain, use_https = self._get_project_domain(
+            project,
+            external_version_slug=version_slug if external else None,
         )
-        protocol = "https" if use_https_protocol else "http"
-
+        protocol = "https" if use_https else "http"
         path = self.resolve_path(project, filename=filename, **kwargs)
         return urlunparse((protocol, domain, path, "", query_params, ""))
 
@@ -211,26 +251,14 @@ def get_subproject_url_prefix(self, project, external_version_slug=None):
         :param project: Project object to get the root URL from
         :param external_version_slug: If given, resolve using the external version domain.
         """
-        canonical_project = self._get_canonical_project(project)
-        use_custom_domain = self._use_cname(canonical_project)
-        custom_domain = canonical_project.get_canonical_custom_domain()
-        if external_version_slug:
-            domain = self._get_external_subdomain(
-                canonical_project, external_version_slug
-            )
-            use_https = settings.PUBLIC_DOMAIN_USES_HTTPS
-        elif use_custom_domain and custom_domain:
-            domain = custom_domain.domain
-            use_https = custom_domain.https
-        else:
-            domain = self._get_project_subdomain(canonical_project)
-            use_https = settings.PUBLIC_DOMAIN_USES_HTTPS
-
+        domain, use_https = self._get_project_domain(
+            project, external_version_slug=external_version_slug
+        )
         protocol = "https" if use_https else "http"
         path = project.subproject_prefix
         return urlunparse((protocol, domain, path, "", "", ""))
 
-    def _get_canonical_project_data(self, project):
+    def _get_canonical_project(self, project):
         """
         Get the parent project and subproject relationship from the canonical project of `project`.
 
@@ -287,38 +315,7 @@ def _get_canonical_project_data(self, project):
         if relationship:
             parent_project = relationship.parent
 
-        return (parent_project, relationship)
-
-    def _get_canonical_project(self, project, projects=None):
-        """
-        Recursively get canonical project for subproject or translations.
-
-        We need to recursively search here as a nested translations inside
-        subprojects, and vice versa, are supported.
-
-        :type project: Project
-        :type projects: List of projects for iteration
-        :rtype: Project
-        """
-        # Track what projects have already been traversed to avoid infinite
-        # recursion. We can't determine a root project well here, so you get
-        # what you get if you have configured your project in a strange manner
-        if projects is None:
-            projects = {project}
-        else:
-            projects.add(project)
-
-        next_project = None
-        if project.main_language_project:
-            next_project = project.main_language_project
-        else:
-            relation = project.parent_relationship
-            if relation:
-                next_project = relation.parent
-
-        if next_project and next_project not in projects:
-            return self._get_canonical_project(next_project, projects)
-        return project
+        return parent_project, relationship
 
     def _get_external_subdomain(self, project, version_slug):
         """Determine domain for an external version."""
@@ -351,28 +348,12 @@ def _fix_filename(self, filename):
         filename = filename.lstrip("/")
         return filename
 
-    def _use_custom_domain(self, custom_domain):
-        """
-        Make decision about whether to use a custom domain to serve docs.
-
-        Always use the custom domain if it exists.
-
-        :param custom_domain: Domain instance or ``None``
-        :type custom_domain: readthedocs.projects.models.Domain
-        """
-        return custom_domain is not None
-
     def _use_cname(self, project):
         """Test if to allow direct serving for project on CNAME."""
         return bool(get_feature(project, feature_type=TYPE_CNAME))
 
 
-class Resolver(SettingsOverrideObject):
-    _default_class = ResolverBase
-    _override_setting = "RESOLVER_CLASS"
-
-
 resolver = Resolver()
 resolve_path = resolver.resolve_path
-resolve_domain = resolver.resolve_domain
+resolve_domain = resolver.get_domain_without_protocol
 resolve = resolver.resolve