Addon manager: install dependencies (#5376)

Addon Manager: Dependency Installation

The Addon Manager can now attempt to use pip directly to install
required packages as specified in either metadata.txt or
requirements.txt files provided by AddOns. The packages are installed
into FreeCAD.getUserAppDataDir()/AdditionalPythonPackages directory.
Only simplified requirements.txt data is supported: any version
information is stripped out, and only packages are supported (that is,
no pip arguments, included files, etc.). Further, packages are checked
against a list of allowed packages prior to being suggested for
installation. Addon authors should submit a PR to the FreeCAD repo
adding their requirements to the allowed list, for packages that are not
already on the list (this is a malware-prevention mechanism).

src/Mod/AddonManager/addonmanager_metadata.py

@@ -25,7 +25,7 @@ import FreeCAD
 import os
 import io
 import hashlib
-from typing import Dict, List
+from typing import Dict, List, Set
 
 from PySide2 import QtCore, QtNetwork
 from PySide2.QtCore import QObject
@@ -53,6 +53,16 @@ class DownloadWorker(QObject):
             QtNetwork.QNetworkRequest.RedirectPolicyAttribute,
             QtNetwork.QNetworkRequest.UserVerifiedRedirectPolicy,
         )
+        self.request.setAttribute(
+            QtNetwork.QNetworkRequest.CacheSaveControlAttribute, True
+        )
+        self.request.setAttribute(
+            QtNetwork.QNetworkRequest.CacheLoadControlAttribute,
+            QtNetwork.QNetworkRequest.PreferCache,
+        )
+        self.request.setAttribute(
+            QtNetwork.QNetworkRequest.BackgroundRequestAttribute, True
+        )
 
         self.fetch_task = network_manager.get(self.request)
         self.fetch_task.finished.connect(self.resolve_fetch)
@@ -188,7 +198,7 @@ class MetadataDownloadWorker(DownloadWorker):
         self.updated.emit(self.repo)
 
 
-class DependencyDownloadWorker(DownloadWorker):
+class MetadataTxtDownloadWorker(DownloadWorker):
     """A worker for downloading metadata.txt"""
 
     def __init__(self, parent, repo: AddonManagerRepo):
@@ -239,17 +249,67 @@ class DependencyDownloadWorker(DownloadWorker):
             elif line.startswith("pylibs="):
                 depspy = line.split("=")[1].split(",")
                 for pl in depspy:
-                    if pl.strip():
-                        self.repo.python_requires.add(pl.strip())
+                    dep = pl.strip()
+                    if dep:
+                        self.repo.python_requires.add(dep)
                         FreeCAD.Console.PrintLog(
-                            f"{self.repo.display_name} requires python package '{pl.strip()}'\n"
+                            f"{self.repo.display_name} requires python package '{dep}'\n"
                         )
+
             elif line.startswith("optionalpylibs="):
                 opspy = line.split("=")[1].split(",")
                 for pl in opspy:
-                    if pl.strip():
-                        self.repo.python_optional.add(pl.strip())
+                    dep = pl.strip()
+                    if dep:
+                        self.repo.python_optional.add(dep)
                         FreeCAD.Console.PrintLog(
                             f"{self.repo.display_name} optionally imports python package '{pl.strip()}'\n"
                         )
         self.updated.emit(self.repo)
+
+
+class RequirementsTxtDownloadWorker(DownloadWorker):
+    """A worker for downloading requirements.txt"""
+
+    def __init__(self, parent, repo: AddonManagerRepo):
+        super().__init__(parent, utils.construct_git_url(repo, "requirements.txt"))
+        self.repo = repo
+
+    def resolve_fetch(self):
+        """Called when the data fetch completed, either with an error, or if it found the metadata file"""
+
+        if self.fetch_task.error() == QtNetwork.QNetworkReply.NetworkError.NoError:
+            FreeCAD.Console.PrintLog(
+                f"Found a requirements.txt file for {self.repo.name}\n"
+            )
+            new_deps = self.fetch_task.readAll()
+            self.parse_file(new_deps.data().decode("utf8"))
+        elif (
+            self.fetch_task.error()
+            == QtNetwork.QNetworkReply.NetworkError.ContentNotFoundError
+        ):
+            pass
+        elif (
+            self.fetch_task.error()
+            == QtNetwork.QNetworkReply.NetworkError.OperationCanceledError
+        ):
+            pass
+        else:
+            FreeCAD.Console.PrintWarning(
+                translate("AddonsInstaller", "Failed to connect to URL")
+                + f":\n{self.url}\n {self.fetch_task.error()}\n"
+            )
+
+    def parse_file(self, data: str) -> None:
+        f = io.StringIO(data)
+        lines = f.readlines()
+        for line in lines:
+            break_chars = " <>=~!+#"
+            package = line
+            for n, c in enumerate(line):
+                if c in break_chars:
+                    package = line[:n].strip()
+                    break
+            if package:
+                self.repo.python_requires.add(package)
+        self.updated.emit(self.repo)