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

conan/tools/files/files.py

@@ -11,6 +11,7 @@
 from fnmatch import fnmatch
 
 import six
+import urllib
 
 from conan.tools import CONAN_TOOLCHAIN_ARGS_FILE, CONAN_TOOLCHAIN_ARGS_SECTION
 from conan.tools.apple.apple import is_apple_os
@@ -165,10 +166,11 @@ 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
+        local_filesystem = True if file_url.startswith("file:") else False
         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)
+                    user_download=True, url=file_url, local_filesystem=local_filesystem,
+                    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)):

conans/client/downloaders/download.py

@@ -1,11 +1,14 @@
 from conans.client.downloaders.cached_file_downloader import CachedFileDownloader
 from conans.client.downloaders.file_downloader import FileDownloader
+from conans.client.downloaders.local_file_downloader import LocalFileDownloader
 
 
-def run_downloader(requester, output, verify, retry, retry_wait, download_cache, user_download=False,
-                   **kwargs):
+def run_downloader(requester, output, verify, retry, retry_wait, download_cache, local_filesystem,
+                   user_download=False, **kwargs):
     downloader = FileDownloader(requester=requester, output=output, verify=verify,
                                 config_retry=retry, config_retry_wait=retry_wait)
-    if download_cache:
+    if local_filesystem:
+        downloader = LocalFileDownloader(output=output)
+    elif download_cache:
         downloader = CachedFileDownloader(download_cache, downloader, user_download=user_download)
     return downloader.download(**kwargs)

conans/client/downloaders/local_file_downloader.py

@@ -0,0 +1,29 @@
+import os
+from urllib.parse import urlparse
+from urllib.request import url2pathname
+from shutil import copyfile
+
+from conans.client.tools.files import check_md5, check_sha1, check_sha256
+from conans.errors import ConanException
+
+
+class LocalFileDownloader(object):
+
+    def __init__(self, output):
+        self._output = output
+
+    def download(self, url, file_path, md5=None, sha1=None, sha256=None, **kwargs):
+
+        file_origin = self._path_from_file_uri(url)
+        copyfile(file_origin, file_path)
+
+        if md5:
+            check_md5(file_path, md5)
+        if sha1:
+            check_sha1(file_path, sha1)
+        if sha256:
+            check_sha256(file_path, sha256)
+
+    def _path_from_file_uri(self, uri):
+       path = urlparse(uri).path
+       return url2pathname(path)

conans/requirements_dev.txt

@@ -1,6 +1,7 @@
 pytest>=6.1.1, <7.0.0; python_version > '3.0'
 pytest>=4.6.11; python_version < '3.0'
 pytest-xdist  # To launch in N cores with pytest -n
+pyfakefs>=4.5.6
 parameterized>=0.6.3
 mock>=1.3.0, <1.4.0
 WebTest>=2.0.18, <2.1.0

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

@@ -1,4 +1,5 @@
 import os
+import platform
 
 import pytest
 import requests
@@ -157,6 +158,33 @@ 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, fs):
+        conanfile = ConanFileMock()
+        conanfile._conan_requester = requests
+
+        file_location = '/path/to/file.txt'
+        if platform.system() == "Windows":
+            file_location = "C:" + file_location
+        fs.create_file(file_location, contents=b'this is some content\n')
+        file_url = f"file:///{file_location}"
+        file_md5 = "a0b156435474e688206c68e5c66a3327"
+
+        dest = os.path.join(temp_folder(), "file.txt")
+        download(conanfile, file_url, dest, md5=file_md5)
+        content = load(dest)
+        assert "this is some content" == content.rstrip()
+
+    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():