zulip/zerver/tests/test_upload_s3.py

import os
import re
from io import BytesIO, StringIO
from unittest.mock import patch
from urllib.parse import urlsplit

import botocore.exceptions
import pyvips
from django.conf import settings

import zerver.lib.upload
from zerver.actions.create_user import do_create_user
from zerver.actions.user_settings import do_delete_avatar_image
from zerver.lib.avatar_hash import user_avatar_path
from zerver.lib.create_user import copy_default_settings
from zerver.lib.test_classes import ZulipTestCase
from zerver.lib.test_helpers import (
    create_s3_buckets,
    get_test_image_file,
    read_test_image_file,
    use_s3_backend,
)
from zerver.lib.thumbnail import (
    DEFAULT_AVATAR_SIZE,
    MEDIUM_AVATAR_SIZE,
    THUMBNAIL_OUTPUT_FORMATS,
    BadImageError,
    resize_avatar,
    resize_emoji,
)
from zerver.lib.upload import (
    all_message_attachments,
    delete_export_tarball,
    delete_message_attachment,
    delete_message_attachments,
    save_attachment_contents,
    upload_export_tarball,
    upload_message_attachment,
)
from zerver.lib.upload.s3 import S3UploadBackend
from zerver.models import Attachment, RealmEmoji, UserProfile
from zerver.models.realms import get_realm
from zerver.models.users import get_system_bot


class S3Test(ZulipTestCase):
    @use_s3_backend
    def test_upload_message_attachment(self) -> None:
        bucket = create_s3_buckets(settings.S3_AUTH_UPLOADS_BUCKET)[0]

        user_profile = self.example_user("hamlet")
        url = upload_message_attachment("dummy.txt", "text/plain", b"zulip!", user_profile)[0]

        base = "/user_uploads/"
        self.assertEqual(base, url[: len(base)])
        path_id = re.sub(r"/user_uploads/", "", url)
        content = bucket.Object(path_id).get()["Body"].read()
        self.assertEqual(b"zulip!", content)

        uploaded_file = Attachment.objects.get(owner=user_profile, path_id=path_id)
        self.assert_length(b"zulip!", uploaded_file.size)

        self.subscribe(self.example_user("hamlet"), "Denmark")
        body = f"First message ...[zulip.txt](http://{user_profile.realm.host}{url})"
        self.send_stream_message(self.example_user("hamlet"), "Denmark", body, "test")

    @use_s3_backend
    def test_save_attachment_contents(self) -> None:
        create_s3_buckets(settings.S3_AUTH_UPLOADS_BUCKET)
        user_profile = self.example_user("hamlet")
        url = upload_message_attachment("dummy.txt", "text/plain", b"zulip!", user_profile)[0]

        path_id = re.sub(r"/user_uploads/", "", url)
        output = BytesIO()
        save_attachment_contents(path_id, output)
        self.assertEqual(output.getvalue(), b"zulip!")

    @use_s3_backend
    def test_upload_message_attachment_s3_cross_realm_path(self) -> None:
        """
        Verifies that the path of a file uploaded by a cross-realm bot to another
        realm is correct.
        """
        create_s3_buckets(settings.S3_AUTH_UPLOADS_BUCKET)

        internal_realm = get_realm(settings.SYSTEM_BOT_REALM)
        zulip_realm = get_realm("zulip")
        user_profile = get_system_bot(settings.EMAIL_GATEWAY_BOT, internal_realm.id)
        self.assertEqual(user_profile.realm, internal_realm)

        url = upload_message_attachment(
            "dummy.txt", "text/plain", b"zulip!", user_profile, zulip_realm
        )[0]
        # Ensure the correct realm id of the target realm is used instead of the bot's realm.
        self.assertTrue(url.startswith(f"/user_uploads/{zulip_realm.id}/"))

    @use_s3_backend
    def test_delete_message_attachment(self) -> None:
        bucket = create_s3_buckets(settings.S3_AUTH_UPLOADS_BUCKET)[0]

        user_profile = self.example_user("hamlet")
        url = upload_message_attachment("dummy.txt", "text/plain", b"zulip!", user_profile)[0]

        path_id = re.sub(r"/user_uploads/", "", url)
        self.assertIsNotNone(bucket.Object(path_id).get())
        self.assertTrue(delete_message_attachment(path_id))
        with self.assertRaises(botocore.exceptions.ClientError):
            bucket.Object(path_id).load()

    @use_s3_backend
    def test_delete_message_attachments(self) -> None:
        bucket = create_s3_buckets(settings.S3_AUTH_UPLOADS_BUCKET)[0]

        user_profile = self.example_user("hamlet")
        path_ids = []
        for n in range(1, 5):
            url = upload_message_attachment("dummy.txt", "text/plain", b"zulip!", user_profile)[0]
            path_id = re.sub(r"/user_uploads/", "", url)
            self.assertIsNotNone(bucket.Object(path_id).get())
            path_ids.append(path_id)

        with patch.object(S3UploadBackend, "delete_message_attachment") as single_delete:
            delete_message_attachments(path_ids)
            single_delete.assert_not_called()
        for path_id in path_ids:
            with self.assertRaises(botocore.exceptions.ClientError):
                bucket.Object(path_id).load()

    @use_s3_backend
    def test_delete_message_attachment_when_file_doesnt_exist(self) -> None:
        bucket = create_s3_buckets(settings.S3_AUTH_UPLOADS_BUCKET)[0]
        with self.assertRaises(botocore.exceptions.ClientError):
            bucket.Object("non-existent-file").load()
        with self.assertLogs(level="WARNING") as warn_log:
            self.assertEqual(False, delete_message_attachment("non-existent-file"))
        self.assertEqual(
            warn_log.output,
            [
                "WARNING:root:non-existent-file does not exist. Its entry in the database will be removed."
            ],
        )

    @use_s3_backend
    def test_all_message_attachments(self) -> None:
        create_s3_buckets(settings.S3_AUTH_UPLOADS_BUCKET)

        user_profile = self.example_user("hamlet")
        path_ids = []
        for n in range(1, 5):
            url = upload_message_attachment("dummy.txt", "text/plain", b"zulip!", user_profile)[0]
            path_ids.append(re.sub(r"/user_uploads/", "", url))

        # Put an image in, which gets thumbnailed
        with self.captureOnCommitCallbacks(execute=True):
            url = upload_message_attachment(
                "img.png", "image/png", read_test_image_file("img.png"), user_profile
            )[0]
            image_path_id = re.sub(r"/user_uploads/", "", url)
            path_ids.append(image_path_id)

        found_paths = [r[0] for r in all_message_attachments()]
        self.assertEqual(sorted(found_paths), sorted(path_ids))

        found_paths = [r[0] for r in all_message_attachments(include_thumbnails=True)]
        for thumbnail_format in THUMBNAIL_OUTPUT_FORMATS:
            if thumbnail_format.animated:
                continue
            path_ids.append(f"thumbnail/{image_path_id}/{thumbnail_format!s}")
        self.assertEqual(sorted(found_paths), sorted(path_ids))

    @use_s3_backend
    def test_user_uploads_authed(self) -> None:
        """
        A call to /json/user_uploads should return a url and actually create an object.
        """
        bucket = create_s3_buckets(settings.S3_AUTH_UPLOADS_BUCKET)[0]

        self.login("hamlet")
        fp = StringIO("zulip!")
        fp.name = "zulip.txt"

        result = self.client_post("/json/user_uploads", {"file": fp})
        response_dict = self.assert_json_success(result)
        self.assertIn("uri", response_dict)
        self.assertIn("url", response_dict)
        base = "/user_uploads/"
        url = response_dict["url"]
        self.assertEqual(response_dict["uri"], url)
        self.assertEqual(base, url[: len(base)])

        # In development, this is just a redirect
        response = self.client_get(url)
        redirect_url = response["Location"]
        path = urlsplit(redirect_url).path
        assert path.startswith("/")
        key = path.removeprefix("/")
        self.assertEqual(b"zulip!", bucket.Object(key).get()["Body"].read())

        prefix = f"/internal/s3/{settings.S3_AUTH_UPLOADS_BUCKET}.s3.amazonaws.com/"
        with self.settings(DEVELOPMENT=False):
            response = self.client_get(url)
        redirect_url = response["X-Accel-Redirect"]
        path = urlsplit(redirect_url).path
        assert path.startswith(prefix)
        key = path.removeprefix(prefix)
        self.assertEqual(b"zulip!", bucket.Object(key).get()["Body"].read())

        # Check the download endpoint
        download_url = url.replace("/user_uploads/", "/user_uploads/download/")
        with self.settings(DEVELOPMENT=False):
            response = self.client_get(download_url)
        redirect_url = response["X-Accel-Redirect"]
        path = urlsplit(redirect_url).path
        assert path.startswith(prefix)
        key = path.removeprefix(prefix)
        self.assertEqual(b"zulip!", bucket.Object(key).get()["Body"].read())

        # Now try the endpoint that's supposed to return a temporary URL for access
        # to the file.
        result = self.client_get("/json" + url)
        data = self.assert_json_success(result)
        url_only_url = data["url"]

        self.assertNotEqual(url_only_url, url)
        self.assertIn("user_uploads/temporary/", url_only_url)
        self.assertTrue(url_only_url.endswith("zulip.txt"))
        # The generated URL has a token authorizing the requester to access the file
        # without being logged in.
        self.logout()
        with self.settings(DEVELOPMENT=False):
            self.client_get(url_only_url)
        redirect_url = response["X-Accel-Redirect"]
        path = urlsplit(redirect_url).path
        assert path.startswith(prefix)
        key = path.removeprefix(prefix)
        self.assertEqual(b"zulip!", bucket.Object(key).get()["Body"].read())

        # The original url shouldn't work when logged out:
        with self.settings(DEVELOPMENT=False):
            result = self.client_get(url)
        self.assertEqual(result.status_code, 302)
        self.assertTrue(result.headers["Location"].endswith(f"/login/?next={url}"))

        hamlet = self.example_user("hamlet")
        self.subscribe(hamlet, "Denmark")
        body = f"First message ...[zulip.txt](http://{hamlet.realm.host}" + url + ")"
        self.send_stream_message(hamlet, "Denmark", body, "test")

    @use_s3_backend
    def test_user_avatars_base(self) -> None:
        backend = zerver.lib.upload.upload_backend
        assert isinstance(backend, S3UploadBackend)
        self.assertEqual(
            backend.construct_public_upload_url_base(),
            f"https://{settings.S3_AVATAR_BUCKET}.s3.amazonaws.com/",
        )

        with self.settings(S3_AVATAR_PUBLIC_URL_PREFIX="https://avatars.example.com"):
            self.assertEqual(
                backend.construct_public_upload_url_base(), "https://avatars.example.com/"
            )

        with self.settings(S3_AVATAR_PUBLIC_URL_PREFIX="https://avatars.example.com/"):
            self.assertEqual(
                backend.construct_public_upload_url_base(), "https://avatars.example.com/"
            )

    @use_s3_backend
    def test_user_avatars_redirect(self) -> None:
        create_s3_buckets(settings.S3_AVATAR_BUCKET)[0]
        self.login("hamlet")
        with get_test_image_file("img.png") as image_file:
            result = self.client_post("/json/users/me/avatar", {"file": image_file})

        response_dict = self.assert_json_success(result)
        self.assertIn("avatar_url", response_dict)
        base = f"https://{settings.S3_AVATAR_BUCKET}.s3.amazonaws.com/"
        url = self.assert_json_success(result)["avatar_url"]
        self.assertEqual(base, url[: len(base)])

        # Try hitting the equivalent `/user_avatars` endpoint
        wrong_url = "/user_avatars/" + url.removeprefix(base)
        result = self.client_get(wrong_url)
        self.assertEqual(result.status_code, 301)
        self.assertEqual(result["Location"], url)

    @use_s3_backend
    def test_upload_avatar_image(self) -> None:
        bucket = create_s3_buckets(settings.S3_AVATAR_BUCKET)[0]

        user_profile = self.example_user("hamlet")
        path_id = user_avatar_path(user_profile)
        original_image_path_id = path_id + ".original"
        medium_path_id = path_id + "-medium.png"

        with get_test_image_file("img.png") as image_file:
            zerver.lib.upload.upload_avatar_image(image_file, user_profile, future=False)
        test_image_data = read_test_image_file("img.png")
        test_medium_image_data = resize_avatar(test_image_data, MEDIUM_AVATAR_SIZE)

        original_image_key = bucket.Object(original_image_path_id)
        self.assertEqual(original_image_key.key, original_image_path_id)
        image_data = original_image_key.get()["Body"].read()
        self.assertEqual(image_data, test_image_data)

        medium_image_key = bucket.Object(medium_path_id)
        self.assertEqual(medium_image_key.key, medium_path_id)
        medium_image_data = medium_image_key.get()["Body"].read()
        self.assertEqual(medium_image_data, test_medium_image_data)

        bucket.Object(medium_image_key.key).delete()
        zerver.lib.upload.ensure_avatar_image(user_profile, medium=True)
        medium_image_key = bucket.Object(medium_path_id)
        self.assertEqual(medium_image_key.key, medium_path_id)

    @use_s3_backend
    def test_copy_avatar_image(self) -> None:
        bucket = create_s3_buckets(settings.S3_AVATAR_BUCKET)[0]

        self.login("hamlet")
        with get_test_image_file("img.png") as image_file:
            self.client_post("/json/users/me/avatar", {"file": image_file})

        source_user_profile = self.example_user("hamlet")
        target_user_profile = do_create_user(
            "user@zulip.com", "password", get_realm("zulip"), "user", acting_user=None
        )

        copy_default_settings(source_user_profile, target_user_profile)

        source_path_id = user_avatar_path(source_user_profile)
        target_path_id = user_avatar_path(target_user_profile)
        self.assertNotEqual(source_path_id, target_path_id)

        source_image_key = bucket.Object(source_path_id + ".png")
        target_image_key = bucket.Object(target_path_id + ".png")
        self.assertEqual(target_image_key.key, target_path_id + ".png")
        self.assertEqual(source_image_key.content_type, target_image_key.content_type)
        source_image_data = source_image_key.get()["Body"].read()
        target_image_data = target_image_key.get()["Body"].read()

        source_original_image_path_id = source_path_id + ".original"
        target_original_image_path_id = target_path_id + ".original"
        target_original_image_key = bucket.Object(target_original_image_path_id)
        self.assertEqual(target_original_image_key.key, target_original_image_path_id)
        source_original_image_key = bucket.Object(source_original_image_path_id)
        self.assertEqual(
            source_original_image_key.content_type, target_original_image_key.content_type
        )
        source_image_data = source_original_image_key.get()["Body"].read()
        target_image_data = target_original_image_key.get()["Body"].read()
        self.assertEqual(source_image_data, target_image_data)

        target_medium_path_id = target_path_id + "-medium.png"
        source_medium_path_id = source_path_id + "-medium.png"
        source_medium_image_key = bucket.Object(source_medium_path_id)
        target_medium_image_key = bucket.Object(target_medium_path_id)
        self.assertEqual(target_medium_image_key.key, target_medium_path_id)
        self.assertEqual(source_medium_image_key.content_type, target_medium_image_key.content_type)
        source_medium_image_data = source_medium_image_key.get()["Body"].read()
        target_medium_image_data = target_medium_image_key.get()["Body"].read()
        self.assertEqual(source_medium_image_data, target_medium_image_data)

    @use_s3_backend
    def test_ensure_avatar_image(self) -> None:
        bucket = create_s3_buckets(settings.S3_AVATAR_BUCKET)[0]

        user_profile = self.example_user("hamlet")
        base_file_path = user_avatar_path(user_profile)
        file_path = base_file_path + ".png"
        original_file_path = base_file_path + ".original"
        medium_file_path = base_file_path + "-medium.png"

        with get_test_image_file("img.png") as image_file:
            zerver.lib.upload.upload_avatar_image(image_file, user_profile, future=False)

        key = bucket.Object(original_file_path)
        image_data = key.get()["Body"].read()

        zerver.lib.upload.ensure_avatar_image(user_profile)
        resized_avatar = resize_avatar(image_data)
        key = bucket.Object(file_path)
        self.assertEqual(resized_avatar, key.get()["Body"].read())

        zerver.lib.upload.ensure_avatar_image(user_profile, medium=True)
        resized_avatar = resize_avatar(image_data, MEDIUM_AVATAR_SIZE)
        key = bucket.Object(medium_file_path)
        self.assertEqual(resized_avatar, key.get()["Body"].read())

    @use_s3_backend
    def test_delete_avatar_image(self) -> None:
        bucket = create_s3_buckets(settings.S3_AVATAR_BUCKET)[0]

        self.login("hamlet")
        with get_test_image_file("img.png") as image_file:
            self.client_post("/json/users/me/avatar", {"file": image_file})

        user = self.example_user("hamlet")

        avatar_base_path = user_avatar_path(user)
        avatar_path_id = avatar_base_path + ".png"
        avatar_original_image_path_id = avatar_base_path + ".original"
        avatar_medium_path_id = avatar_base_path + "-medium.png"

        self.assertEqual(user.avatar_source, UserProfile.AVATAR_FROM_USER)
        self.assertIsNotNone(bucket.Object(avatar_path_id))
        self.assertIsNotNone(bucket.Object(avatar_original_image_path_id))
        self.assertIsNotNone(bucket.Object(avatar_medium_path_id))

        do_delete_avatar_image(user, acting_user=user)

        self.assertEqual(user.avatar_source, UserProfile.AVATAR_FROM_GRAVATAR)

        # Confirm that the avatar files no longer exist in S3.
        with self.assertRaises(botocore.exceptions.ClientError):
            bucket.Object(avatar_path_id).load()
        with self.assertRaises(botocore.exceptions.ClientError):
            bucket.Object(avatar_original_image_path_id).load()
        with self.assertRaises(botocore.exceptions.ClientError):
            bucket.Object(avatar_medium_path_id).load()

    @use_s3_backend
    def test_upload_realm_icon_image(self) -> None:
        bucket = create_s3_buckets(settings.S3_AVATAR_BUCKET)[0]

        user_profile = self.example_user("hamlet")
        with get_test_image_file("img.png") as image_file:
            zerver.lib.upload.upload_backend.upload_realm_icon_image(
                image_file, user_profile, content_type="image/png"
            )

        original_path_id = os.path.join(str(user_profile.realm.id), "realm", "icon.original")
        original_key = bucket.Object(original_path_id)
        self.assertEqual(read_test_image_file("img.png"), original_key.get()["Body"].read())

        resized_path_id = os.path.join(str(user_profile.realm.id), "realm", "icon.png")
        resized_data = bucket.Object(resized_path_id).get()["Body"].read()
        resized_image = pyvips.Image.new_from_buffer(resized_data, "")
        self.assertEqual(DEFAULT_AVATAR_SIZE, resized_image.height)
        self.assertEqual(DEFAULT_AVATAR_SIZE, resized_image.width)

    @use_s3_backend
    def _test_upload_logo_image(self, night: bool, file_name: str) -> None:
        bucket = create_s3_buckets(settings.S3_AVATAR_BUCKET)[0]

        user_profile = self.example_user("hamlet")
        with get_test_image_file("img.png") as image_file:
            zerver.lib.upload.upload_backend.upload_realm_logo_image(
                image_file, user_profile, night, "image/png"
            )

        original_path_id = os.path.join(
            str(user_profile.realm.id), "realm", f"{file_name}.original"
        )
        original_key = bucket.Object(original_path_id)
        self.assertEqual(read_test_image_file("img.png"), original_key.get()["Body"].read())

        resized_path_id = os.path.join(str(user_profile.realm.id), "realm", f"{file_name}.png")
        resized_data = bucket.Object(resized_path_id).get()["Body"].read()
        resized_image = pyvips.Image.new_from_buffer(resized_data, "")
        self.assertEqual(DEFAULT_AVATAR_SIZE, resized_image.height)
        self.assertEqual(DEFAULT_AVATAR_SIZE, resized_image.width)

    def test_upload_realm_logo_image(self) -> None:
        self._test_upload_logo_image(night=False, file_name="logo")
        self._test_upload_logo_image(night=True, file_name="night_logo")

    @use_s3_backend
    def test_get_emoji_url(self) -> None:
        emoji_name = "emoji.png"
        realm_id = 1
        bucket = settings.S3_AVATAR_BUCKET
        path = RealmEmoji.PATH_ID_TEMPLATE.format(realm_id=realm_id, emoji_file_name=emoji_name)

        url = zerver.lib.upload.upload_backend.get_emoji_url("emoji.png", realm_id)

        expected_url = f"https://{bucket}.s3.amazonaws.com/{path}"
        self.assertEqual(expected_url, url)

        emoji_name = "animated_image.gif"

        path = RealmEmoji.PATH_ID_TEMPLATE.format(realm_id=realm_id, emoji_file_name=emoji_name)
        still_path = RealmEmoji.STILL_PATH_ID_TEMPLATE.format(
            realm_id=realm_id, emoji_filename_without_extension=os.path.splitext(emoji_name)[0]
        )

        url = zerver.lib.upload.upload_backend.get_emoji_url("animated_image.gif", realm_id)
        still_url = zerver.lib.upload.upload_backend.get_emoji_url(
            "animated_image.gif", realm_id, still=True
        )

        expected_url = f"https://{bucket}.s3.amazonaws.com/{path}"
        self.assertEqual(expected_url, url)
        expected_still_url = f"https://{bucket}.s3.amazonaws.com/{still_path}"
        self.assertEqual(expected_still_url, still_url)

    @use_s3_backend
    def test_upload_emoji_image(self) -> None:
        bucket = create_s3_buckets(settings.S3_AVATAR_BUCKET)[0]

        user_profile = self.example_user("hamlet")
        emoji_name = "animated_img.gif"
        with get_test_image_file(emoji_name) as image_file:
            zerver.lib.upload.upload_emoji_image(image_file, emoji_name, user_profile, "image/gif")

        emoji_path = RealmEmoji.PATH_ID_TEMPLATE.format(
            realm_id=user_profile.realm_id,
            emoji_file_name=emoji_name,
        )
        original_key = bucket.Object(emoji_path + ".original")
        self.assertEqual(read_test_image_file(emoji_name), original_key.get()["Body"].read())

        self.assertEqual(os.path.splitext(emoji_path)[1], ".gif")
        bucket_data = bucket.Object(emoji_path).get()
        self.assertEqual(bucket_data["ContentType"], "image/gif")
        resized_image = pyvips.Image.new_from_buffer(bucket_data["Body"].read(), "")
        self.assertEqual(resized_image.get("vips-loader"), "gifload_buffer")

        still_path = RealmEmoji.STILL_PATH_ID_TEMPLATE.format(
            realm_id=user_profile.realm_id,
            emoji_filename_without_extension=os.path.splitext(emoji_name)[0],
        )
        self.assertEqual(os.path.splitext(still_path)[1], ".png")
        bucket_data = bucket.Object(still_path).get()
        self.assertEqual(bucket_data["ContentType"], "image/png")
        still_image = pyvips.Image.new_from_buffer(bucket_data["Body"].read(), "")
        self.assertEqual(still_image.get("vips-loader"), "pngload_buffer")

    @use_s3_backend
    def test_upload_emoji_non_image(self) -> None:
        create_s3_buckets(settings.S3_AVATAR_BUCKET)[0]

        user_profile = self.example_user("hamlet")
        emoji_name = "emoji.png"
        with get_test_image_file("text.txt") as image_file:
            with patch("zerver.lib.upload.resize_emoji", side_effect=resize_emoji) as resize_mock:
                with self.assertRaises(BadImageError):
                    # We trust the content-type and fail when we try to load the image
                    zerver.lib.upload.upload_emoji_image(
                        image_file, emoji_name, user_profile, "image/png"
                    )
                resize_mock.assert_called_once()

            with patch("zerver.lib.upload.resize_emoji", side_effect=resize_emoji) as resize_mock:
                with self.assertRaises(BadImageError):
                    # We trust the content-type and abort before trying to load
                    zerver.lib.upload.upload_emoji_image(
                        image_file, emoji_name, user_profile, "text/plain"
                    )
                resize_mock.assert_not_called()

    @use_s3_backend
    def test_tarball_upload_and_deletion(self) -> None:
        bucket = create_s3_buckets(settings.S3_AVATAR_BUCKET)[0]

        user_profile = self.example_user("iago")
        self.assertTrue(user_profile.is_realm_admin)

        tarball_path = os.path.join(settings.TEST_WORKER_DIR, "tarball.tar.gz")
        with open(tarball_path, "w") as f:
            f.write("dummy")

        total_bytes_transferred = 0

        def percent_callback(bytes_transferred: int) -> None:
            nonlocal total_bytes_transferred
            total_bytes_transferred += bytes_transferred

        url = upload_export_tarball(
            user_profile.realm, tarball_path, percent_callback=percent_callback
        )
        # Verify the percent_callback API works
        self.assertEqual(total_bytes_transferred, 5)

        result = re.search(re.compile(r"([0-9a-fA-F]{32})"), url)
        if result is not None:
            hex_value = result.group(1)
        expected_url = f"https://{bucket.name}.s3.amazonaws.com/exports/{hex_value}/{os.path.basename(tarball_path)}"
        self.assertEqual(url, expected_url)

        # Delete the tarball.
        with self.assertLogs(level="WARNING") as warn_log:
            self.assertIsNone(delete_export_tarball("/not_a_file"))
        self.assertEqual(
            warn_log.output,
            ["WARNING:root:not_a_file does not exist. Its entry in the database will be removed."],
        )
        path_id = urlsplit(url).path
        self.assertEqual(delete_export_tarball(path_id), path_id)