Add ability to reference files in the local filesystem with file:// s… (

#11569)

* Add ability to reference files in the local filesystem with file:// specifier

* Add pyfakefs to requirements_dev

* Add implementation for local file downloader

* Move implementation to files.py

* Fix implementation

* Use temp folder instead of pyfakefs

* Undo redundant changes in download.py

* Fix file loading and md5 checksum

conan/tools/files/files.py

@@ -11,6 +11,8 @@
 from fnmatch import fnmatch
 
 import six
+from urllib.parse import urlparse
+from urllib.request import url2pathname
 
 from conan.tools import CONAN_TOOLCHAIN_ARGS_FILE, CONAN_TOOLCHAIN_ARGS_SECTION
 from conan.tools.apple.apple import is_apple_os
@@ -165,10 +167,13 @@ def download(conanfile, url, filename, verify=True, retry=None, retry_wait=None,
 
     def _download_file(file_url):
         # The download cache is only used if a checksum is provided, otherwise, a normal download
-        run_downloader(requester=requester, output=out, verify=verify, download_cache=download_cache,
-                       user_download=True, url=file_url,
-                       file_path=filename, retry=retry, retry_wait=retry_wait, overwrite=overwrite,
-                       auth=auth, headers=headers, md5=md5, sha1=sha1, sha256=sha256)
+        if file_url.startswith("file:"):
+            _copy_local_file_from_uri(conanfile, url=file_url, file_path=filename, md5=md5, sha1=sha1, sha256=sha256)
+        else:
+            run_downloader(requester=requester, output=out, verify=verify, download_cache=download_cache,
+                        user_download=True, url=file_url,
+                        file_path=filename, retry=retry, retry_wait=retry_wait, overwrite=overwrite,
+                        auth=auth, headers=headers, md5=md5, sha1=sha1, sha256=sha256)
         out.writeln("")
 
     if not isinstance(url, (list, tuple)):
@@ -184,6 +189,21 @@ def _download_file(file_url):
         else:
             raise ConanException("All downloads from ({}) URLs have failed.".format(len(url)))
 
+def _copy_local_file_from_uri(conanfile, url, file_path, md5=None, sha1=None, sha256=None):
+    file_origin = _path_from_file_uri(url)
+    shutil.copyfile(file_origin, file_path)
+
+    if md5:
+        check_md5(conanfile, file_path, md5)
+    if sha1:
+        check_sha1(conanfile, file_path, sha1)
+    if sha256:
+        check_sha256(conanfile, file_path, sha256)
+
+def _path_from_file_uri(uri):
+    path = urlparse(uri).path
+    return url2pathname(path)
+
 
 def rename(conanfile, src, dst):
     """

conans/test/unittests/tools/files/test_downloads.py

@@ -1,4 +1,5 @@
 import os
+import platform
 
 import pytest
 import requests
@@ -157,6 +158,32 @@ def test_download_no_retries_errors(self, bottle_server):
         assert "Waiting" not in str(conanfile.output)
         assert "retry" not in str(conanfile.output)
 
+    def test_download_localfile(self):
+        conanfile = ConanFileMock()
+        conanfile._conan_requester = requests
+
+        file_location =  os.path.join(temp_folder(), "file.txt")
+        save(file_location, "this is some content")
+
+        file_url = f"file:///{file_location}"
+        file_md5 = "736db904ad222bf88ee6b8d103fceb8e"
+
+        dest = os.path.join(temp_folder(), "downloaded_file.txt")
+        download(conanfile, file_url, dest, md5=file_md5)
+        content = load(dest)
+        assert "this is some content" == content
+
+    def test_download_localfile_notfound(self):
+        conanfile = ConanFileMock()
+        conanfile._conan_requester = requests
+
+        file_url = "file:///path/to/missing/file.txt"
+        dest = os.path.join(temp_folder(), "file.txt")
+
+        with pytest.raises(FileNotFoundError) as exc:
+            download(conanfile, file_url, dest)
+
+        assert "No such file" in str(exc.value)
 
 @pytest.fixture()
 def bottle_server_zip():