Adding support for patch inside subfolder

[javirst]

rpatchur.yml
patch_url: http://myservername.com/patch/

plist.txt
1 luas/update.thor

with those config the patcher will result in Error
Failure: Failed to download patches: Failed to create temporary file: The system cannot find the path specified. (os error 3)

can we add a support for downloading inside a subfolder ?

[L1nkZ]

That is definitely a bug. Thanks for the report!

[Kokotewa]

Reviewing this, I think I know what the issue is, but I don't know how to solve it (read: I'm not a rust developer).

The crux of the issue is here (core.rs#L418),

        let patch_file_url = patch_url
            .join(patch_info.file_name.as_str())
            .with_context(|| "Failed to generate URL for patch file")?;
        let local_file_path = download_directory
            .as_ref()
            .join(patch_info.file_name.as_str());
        let mut tmp_file = File::create(&local_file_path)
            .await
            .with_context(|| "Failed to create temporary file")?;

When we attempt to download a nested file from plist, e.g. $web/patch_url/some_dir/some_file, rpatchur assumes that this is a filename. When it creates a local copy of that file (prior to merging it into the GRF), it creates a temporary copy of the remote file within a temporary directory ($temp_dir/$temp_file). This breaks when translating a nested directory as the path isn't a filename anymore ($temp_dir/$this_is_assumed_to_be_a_file_name_but_it_is_really_a_dir_and_a_file_name).

The complicated way to address this would be to create temporary nested directories. The easy (and imo "better") way would be change file_name to some unique string, e.g. md5sum(file_name) (circumventing any nested directories and the need to create/manage them).

[Kokotewa]

Following up on this, the update is slightly more complicated than originally conveyed.

within /rpatchur/Cargo.toml
(1) Add sha256 to dependencies

...
[dependencies]
+sha256 = "1.5"

within rpatchur/src/patcher/core.rs
(1) update core.rs to hash the filename digest(patch_info.file_name.as_str())

use sha256::{digest};
...
async fn download_patches_concurrent_inner(
    patch_url: Url,
    patch_list: ThorPatchList,
    download_directory: impl AsRef<Path>,
    ensure_integrity: bool,
    ui_controller: &UiController,
) -> Result<Vec<PendingPatch>> {
...
        let local_file_path = download_directory
            .as_ref()
            .join(patch_info.file_name.as_str());
            .join(digest(patch_info.file_name.as_str()));

(2) address a slight bug that results in the patch_url being built incorrectly

async fn download_patches_concurrent_inner(
    patch_url: Url,
    patch_list: ThorPatchList,
    download_directory: impl AsRef<Path>,
    ensure_integrity: bool,
    ui_controller: &UiController,
) -> Result<Vec<PendingPatch>> {
...
        download_patch_to_file(
            client,
            &patch_url,  // previously &patch_file_url which resulted in a redundant concatenation on line 519
            &patch_info,
            &mut tmp_file,
            &mut progress_callback,
        )
        .await?;