Merge pull request #11 from LaurentMazare/add_hub

Adding candle-hub

Cargo.toml

@@ -2,6 +2,7 @@
 
 members = [
     "candle-core",
+    "candle-hub",
     "candle-kernels",
 ]
 

candle-hub/.gitignore

@@ -0,0 +1,2 @@
+/target
+/Cargo.lock

candle-hub/Cargo.toml

@@ -0,0 +1,30 @@
+[package]
+name = "candle-hub"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+dirs = "5.0.1"
+fs2 = "0.4.3"
+rand = "0.8.5"
+thiserror = "1.0.40"
+futures = { version = "0.3.28", optional = true }
+reqwest = { version = "0.11.18", optional = true, features = ["json"] }
+tokio = { version = "1.28.2", features = ["fs"], optional = true }
+serde = { version = "1.0.164", features = ["derive"], optional = true }
+serde_json = { version = "1.0.97", optional = true }
+indicatif = { version = "0.17.5", optional = true }
+
+[dev-dependencies]
+rand = "0.8.5"
+sha256 = "1.1.4"
+tokio = { version = "1.28.2", features = ["macros"] }
+tokio-test = "0.4.2"
+
+[features]
+default = ["online"]
+online = ["reqwest", "tokio", "futures", "serde", "serde_json", "indicatif"]
+
+

candle-hub/src/api.rs

@@ -0,0 +1,706 @@
+use crate::{Cache, Repo};
+use fs2::FileExt;
+use indicatif::{ProgressBar, ProgressStyle};
+use rand::{distributions::Alphanumeric, thread_rng, Rng};
+use reqwest::{
+    header::{
+        HeaderMap, HeaderName, HeaderValue, InvalidHeaderValue, ToStrError, AUTHORIZATION,
+        CONTENT_RANGE, LOCATION, RANGE, USER_AGENT,
+    },
+    redirect::Policy,
+    Client, Error as ReqwestError,
+};
+use serde::Deserialize;
+use std::num::ParseIntError;
+use std::path::{Component, Path, PathBuf};
+use std::sync::Arc;
+use thiserror::Error;
+use tokio::io::{AsyncSeekExt, AsyncWriteExt, SeekFrom};
+use tokio::sync::{AcquireError, Semaphore, TryAcquireError};
+
+/// Current version (used in user-agent)
+const VERSION: &str = env!("CARGO_PKG_VERSION");
+/// Current name (used in user-agent)
+const NAME: &str = env!("CARGO_PKG_NAME");
+
+#[derive(Debug, Error)]
+/// All errors the API can throw
+pub enum ApiError {
+    /// Api expects certain header to be present in the results to derive some information
+    #[error("Header {0} is missing")]
+    MissingHeader(HeaderName),
+
+    /// The header exists, but the value is not conform to what the Api expects.
+    #[error("Header {0} is invalid")]
+    InvalidHeader(HeaderName),
+
+    /// The value cannot be used as a header during request header construction
+    #[error("Invalid header value {0}")]
+    InvalidHeaderValue(#[from] InvalidHeaderValue),
+
+    /// The header value is not valid utf-8
+    #[error("header value is not a string")]
+    ToStr(#[from] ToStrError),
+
+    /// Error in the request
+    #[error("request error: {0}")]
+    RequestError(#[from] ReqwestError),
+
+    /// Error parsing some range value
+    #[error("Cannot parse int")]
+    ParseIntError(#[from] ParseIntError),
+
+    /// I/O Error
+    #[error("I/O error {0}")]
+    IoError(#[from] std::io::Error),
+
+    /// We tried to download chunk too many times
+    #[error("Too many retries: {0}")]
+    TooManyRetries(Box<ApiError>),
+
+    /// Semaphore cannot be acquired
+    #[error("Try acquire: {0}")]
+    TryAcquireError(#[from] TryAcquireError),
+
+    /// Semaphore cannot be acquired
+    #[error("Acquire: {0}")]
+    AcquireError(#[from] AcquireError),
+    // /// Semaphore cannot be acquired
+    // #[error("Invalid Response: {0:?}")]
+    // InvalidResponse(Response),
+}
+
+/// Siblings are simplified file descriptions of remote files on the hub
+#[derive(Debug, Clone, Deserialize, PartialEq)]
+pub struct Siblings {
+    /// The path within the repo.
+    pub rfilename: String,
+}
+
+/// The description of the repo given by the hub
+#[derive(Debug, Clone, Deserialize, PartialEq)]
+pub struct ModelInfo {
+    /// See [`Siblings`]
+    pub siblings: Vec<Siblings>,
+}
+
+/// Helper to create [`Api`] with all the options.
+pub struct ApiBuilder {
+    endpoint: String,
+    cache: Cache,
+    url_template: String,
+    token: Option<String>,
+    max_files: usize,
+    chunk_size: usize,
+    parallel_failures: usize,
+    max_retries: usize,
+    progress: bool,
+}
+
+impl Default for ApiBuilder {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl ApiBuilder {
+    /// Default api builder
+    /// ```
+    /// use candle_hub::api::ApiBuilder;
+    /// let api = ApiBuilder::new().build().unwrap();
+    /// ```
+    pub fn new() -> Self {
+        let cache = Cache::default();
+        let mut token_filename = cache.path().clone();
+        token_filename.push(".token");
+        let token = match std::fs::read_to_string(token_filename) {
+            Ok(token_content) => {
+                let token_content = token_content.trim();
+                if !token_content.is_empty() {
+                    Some(token_content.to_string())
+                } else {
+                    None
+                }
+            }
+            Err(_) => None,
+        };
+
+        let progress = true;
+
+        Self {
+            endpoint: "https://huggingface.co".to_string(),
+            url_template: "{endpoint}/{repo_id}/resolve/{revision}/{filename}".to_string(),
+            cache,
+            token,
+            max_files: 100,
+            chunk_size: 10_000_000,
+            parallel_failures: 0,
+            max_retries: 0,
+            progress,
+        }
+    }
+
+    /// Wether to show a progressbar
+    pub fn with_progress(mut self, progress: bool) -> Self {
+        self.progress = progress;
+        self
+    }
+
+    /// Changes the location of the cache directory. Defaults is `~/.cache/huggingface/`.
+    pub fn with_cache_dir(mut self, cache_dir: PathBuf) -> Self {
+        self.cache = Cache::new(cache_dir);
+        self
+    }
+
+    fn build_headers(&self) -> Result<HeaderMap, ApiError> {
+        let mut headers = HeaderMap::new();
+        let user_agent = format!("unkown/None; {NAME}/{VERSION}; rust/unknown");
+        headers.insert(USER_AGENT, HeaderValue::from_str(&user_agent)?);
+        if let Some(token) = &self.token {
+            headers.insert(
+                AUTHORIZATION,
+                HeaderValue::from_str(&format!("Bearer {token}"))?,
+            );
+        }
+        Ok(headers)
+    }
+
+    /// Consumes the builder and buids the final [`Api`]
+    pub fn build(self) -> Result<Api, ApiError> {
+        let headers = self.build_headers()?;
+        let client = Client::builder().default_headers(headers.clone()).build()?;
+        let no_redirect_client = Client::builder()
+            .redirect(Policy::none())
+            .default_headers(headers)
+            .build()?;
+        Ok(Api {
+            endpoint: self.endpoint,
+            url_template: self.url_template,
+            cache: self.cache,
+            client,
+
+            no_redirect_client,
+            max_files: self.max_files,
+            chunk_size: self.chunk_size,
+            parallel_failures: self.parallel_failures,
+            max_retries: self.max_retries,
+            progress: self.progress,
+        })
+    }
+}
+
+#[derive(Debug)]
+struct Metadata {
+    commit_hash: String,
+    etag: String,
+    size: usize,
+}
+
+/// The actual Api used to interacto with the hub.
+/// You can inspect repos with [`Api::info`]
+/// or download files with [`Api::download`]
+pub struct Api {
+    endpoint: String,
+    url_template: String,
+    cache: Cache,
+    client: Client,
+    no_redirect_client: Client,
+    max_files: usize,
+    chunk_size: usize,
+    parallel_failures: usize,
+    max_retries: usize,
+    progress: bool,
+}
+
+fn temp_filename() -> PathBuf {
+    let s: String = rand::thread_rng()
+        .sample_iter(&Alphanumeric)
+        .take(7)
+        .map(char::from)
+        .collect();
+    let mut path = std::env::temp_dir();
+    path.push(s);
+    path
+}
+
+fn make_relative(src: &Path, dst: &Path) -> PathBuf {
+    let path = src;
+    let base = dst;
+
+    if path.is_absolute() != base.is_absolute() {
+        panic!("This function is made to look at absolute paths only");
+    }
+    let mut ita = path.components();
+    let mut itb = base.components();
+
+    loop {
+        match (ita.next(), itb.next()) {
+            (Some(a), Some(b)) if a == b => (),
+            (some_a, _) => {
+                // Ignoring b, because 1 component is the filename
+                // for which we don't need to go back up for relative
+                // filename to work.
+                let mut new_path = PathBuf::new();
+                for _ in itb {
+                    new_path.push(Component::ParentDir);
+                }
+                if let Some(a) = some_a {
+                    new_path.push(a);
+                    for comp in ita {
+                        new_path.push(comp);
+                    }
+                }
+                return new_path;
+            }
+        }
+    }
+}
+
+fn symlink_or_rename(src: &Path, dst: &Path) -> Result<(), std::io::Error> {
+    if dst.exists() {
+        return Ok(());
+    }
+
+    let src = make_relative(src, dst);
+    #[cfg(target_os = "windows")]
+    std::os::windows::fs::symlink_file(src, dst)?;
+
+    #[cfg(target_family = "unix")]
+    std::os::unix::fs::symlink(src, dst)?;
+
+    #[cfg(not(any(target_family = "unix", target_os = "windows")))]
+    std::fs::rename(src, dst)?;
+
+    Ok(())
+}
+
+fn jitter() -> usize {
+    thread_rng().gen_range(0..=500)
+}
+
+fn exponential_backoff(base_wait_time: usize, n: usize, max: usize) -> usize {
+    (base_wait_time + n.pow(2) + jitter()).min(max)
+}
+
+impl Api {
+    /// Creates a default Api, for Api options See [`ApiBuilder`]
+    pub fn new() -> Result<Self, ApiError> {
+        ApiBuilder::new().build()
+    }
+
+    /// Get the fully qualified URL of the remote filename
+    /// ```
+    /// # use candle_hub::{api::Api, Repo};
+    /// let api = Api::new().unwrap();
+    /// let repo = Repo::model("gpt2".to_string());
+    /// let url = api.url(&repo, "model.safetensors");
+    /// assert_eq!(url, "https://huggingface.co/gpt2/resolve/main/model.safetensors");
+    /// ```
+    pub fn url(&self, repo: &Repo, filename: &str) -> String {
+        let endpoint = &self.endpoint;
+        let revision = &repo.url_revision();
+        self.url_template
+            .replace("{endpoint}", endpoint)
+            .replace("{repo_id}", &repo.url())
+            .replace("{revision}", revision)
+            .replace("{filename}", filename)
+    }
+
+    /// Get the underlying api client
+    /// Allows for lower level access
+    pub fn client(&self) -> &Client {
+        &self.client
+    }
+
+    async fn metadata(&self, url: &str) -> Result<Metadata, ApiError> {
+        let response = self
+            .no_redirect_client
+            .get(url)
+            .header(RANGE, "bytes=0-0")
+            .send()
+            .await?;
+        let response = response.error_for_status()?;
+        let headers = response.headers();
+        let header_commit = HeaderName::from_static("x-repo-commit");
+        let header_linked_etag = HeaderName::from_static("x-linked-etag");
+        let header_etag = HeaderName::from_static("etag");
+
+        let etag = match headers.get(&header_linked_etag) {
+            Some(etag) => etag,
+            None => headers
+                .get(&header_etag)
+                .ok_or(ApiError::MissingHeader(header_etag))?,
+        };
+        // Cleaning extra quotes
+        let etag = etag.to_str()?.to_string().replace('"', "");
+        let commit_hash = headers
+            .get(&header_commit)
+            .ok_or(ApiError::MissingHeader(header_commit))?
+            .to_str()?
+            .to_string();
+
+        // The response was redirected o S3 most likely which will
+        // know about the size of the file
+        let response = if response.status().is_redirection() {
+            self.client
+                .get(headers.get(LOCATION).unwrap().to_str()?.to_string())
+                .header(RANGE, "bytes=0-0")
+                .send()
+                .await?
+        } else {
+            response
+        };
+        let headers = response.headers();
+        let content_range = headers
+            .get(CONTENT_RANGE)
+            .ok_or(ApiError::MissingHeader(CONTENT_RANGE))?
+            .to_str()?;
+
+        let size = content_range
+            .split('/')
+            .last()
+            .ok_or(ApiError::InvalidHeader(CONTENT_RANGE))?
+            .parse()?;
+        Ok(Metadata {
+            commit_hash,
+            etag,
+            size,
+        })
+    }
+
+    async fn download_tempfile(
+        &self,
+        url: &str,
+        length: usize,
+        progressbar: Option<ProgressBar>,
+    ) -> Result<PathBuf, ApiError> {
+        let mut handles = vec![];
+        let semaphore = Arc::new(Semaphore::new(self.max_files));
+        let parallel_failures_semaphore = Arc::new(Semaphore::new(self.parallel_failures));
+        let filename = temp_filename();
+
+        let chunk_size = self.chunk_size;
+        for start in (0..length).step_by(chunk_size) {
+            let url = url.to_string();
+            let filename = filename.clone();
+            let client = self.client.clone();
+
+            let stop = std::cmp::min(start + chunk_size - 1, length);
+            let permit = semaphore.clone().acquire_owned().await?;
+            let parallel_failures = self.parallel_failures;
+            let max_retries = self.max_retries;
+            let parallel_failures_semaphore = parallel_failures_semaphore.clone();
+            let progress = progressbar.clone();
+            handles.push(tokio::spawn(async move {
+                let mut chunk = Self::download_chunk(&client, &url, &filename, start, stop).await;
+                let mut i = 0;
+                if parallel_failures > 0 {
+                    while let Err(dlerr) = chunk {
+                        let parallel_failure_permit =
+                            parallel_failures_semaphore.clone().try_acquire_owned()?;
+
+                        let wait_time = exponential_backoff(300, i, 10_000);
+                        tokio::time::sleep(tokio::time::Duration::from_millis(wait_time as u64))
+                            .await;
+
+                        chunk = Self::download_chunk(&client, &url, &filename, start, stop).await;
+                        i += 1;
+                        if i > max_retries {
+                            return Err(ApiError::TooManyRetries(dlerr.into()));
+                        }
+                        drop(parallel_failure_permit);
+                    }
+                }
+                drop(permit);
+                if let Some(p) = progress {
+                    p.inc((stop - start) as u64);
+                }
+                chunk
+            }));
+        }
+
+        // Output the chained result
+        let results: Vec<Result<Result<(), ApiError>, tokio::task::JoinError>> =
+            futures::future::join_all(handles).await;
+        let results: Result<(), ApiError> = results.into_iter().flatten().collect();
+        results?;
+        if let Some(p) = progressbar {
+            p.finish()
+        }
+        Ok(filename)
+    }
+
+    async fn download_chunk(
+        client: &reqwest::Client,
+        url: &str,
+        filename: &PathBuf,
+        start: usize,
+        stop: usize,
+    ) -> Result<(), ApiError> {
+        // Process each socket concurrently.
+        let range = format!("bytes={start}-{stop}");
+        let mut file = tokio::fs::OpenOptions::new()
+            .write(true)
+            .create(true)
+            .open(filename)
+            .await?;
+        file.seek(SeekFrom::Start(start as u64)).await?;
+        let response = client
+            .get(url)
+            .header(RANGE, range)
+            .send()
+            .await?
+            .error_for_status()?;
+        let content = response.bytes().await?;
+        file.write_all(&content).await?;
+        Ok(())
+    }
+
+    /// This will attempt the fetch the file locally first, then [`Api.download`]
+    /// if the file is not present.
+    /// ```no_run
+    /// # use candle_hub::{api::ApiBuilder, Repo};
+    /// # tokio_test::block_on(async {
+    /// let api = ApiBuilder::new().build().unwrap();
+    /// let repo = Repo::model("gpt2".to_string());
+    /// let local_filename = api.get(&repo, "model.safetensors").await.unwrap();
+    /// # })
+    pub async fn get(&self, repo: &Repo, filename: &str) -> Result<PathBuf, ApiError> {
+        if let Some(path) = self.cache.get(repo, filename) {
+            Ok(path)
+        } else {
+            self.download(repo, filename).await
+        }
+    }
+
+    /// Downloads a remote file (if not already present) into the cache directory
+    /// to be used locally.
+    /// This functions require internet access to verify if new versions of the file
+    /// exist, even if a file is already on disk at location.
+    /// ```no_run
+    /// # use candle_hub::{api::ApiBuilder, Repo};
+    /// # tokio_test::block_on(async {
+    /// let api = ApiBuilder::new().build().unwrap();
+    /// let repo = Repo::model("gpt2".to_string());
+    /// let local_filename = api.download(&repo, "model.safetensors").await.unwrap();
+    /// # })
+    /// ```
+    pub async fn download(&self, repo: &Repo, filename: &str) -> Result<PathBuf, ApiError> {
+        let url = self.url(repo, filename);
+        let metadata = self.metadata(&url).await?;
+
+        let blob_path = self.cache.blob_path(repo, &metadata.etag);
+        std::fs::create_dir_all(blob_path.parent().unwrap())?;
+
+        let file1 = std::fs::OpenOptions::new()
+            .read(true)
+            .write(true)
+            .create(true)
+            .open(&blob_path)?;
+        file1.lock_exclusive()?;
+
+        let progressbar = if self.progress {
+            let progress = ProgressBar::new(metadata.size as u64);
+            progress.set_style(
+                ProgressStyle::with_template(
+                    "{msg} [{elapsed_precise}] [{wide_bar}] {bytes}/{total_bytes} {bytes_per_sec} ({eta})",
+                )
+                .unwrap(), // .progress_chars("━ "),
+            );
+            let maxlength = 30;
+            let message = if filename.len() > maxlength {
+                format!("..{}", &filename[filename.len() - maxlength..])
+            } else {
+                filename.to_string()
+            };
+            progress.set_message(message);
+            Some(progress)
+        } else {
+            None
+        };
+
+        let tmp_filename = self
+            .download_tempfile(&url, metadata.size, progressbar)
+            .await?;
+        std::fs::copy(tmp_filename, &blob_path)?;
+
+        let mut pointer_path = self.cache.pointer_path(repo, &metadata.commit_hash);
+        pointer_path.push(filename);
+        std::fs::create_dir_all(pointer_path.parent().unwrap()).ok();
+
+        symlink_or_rename(&blob_path, &pointer_path)?;
+        self.cache.create_ref(repo, &metadata.commit_hash)?;
+
+        Ok(pointer_path)
+    }
+
+    /// Get information about the Repo
+    /// ```
+    /// # use candle_hub::{api::Api, Repo};
+    /// # tokio_test::block_on(async {
+    /// let api = Api::new().unwrap();
+    /// let repo = Repo::model("gpt2".to_string());
+    /// api.info(&repo);
+    /// # })
+    /// ```
+    pub async fn info(&self, repo: &Repo) -> Result<ModelInfo, ApiError> {
+        let url = format!("{}/api/{}", self.endpoint, repo.api_url());
+        let response = self.client.get(url).send().await?;
+        let response = response.error_for_status()?;
+
+        let model_info = response.json().await?;
+
+        Ok(model_info)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::RepoType;
+    use rand::{distributions::Alphanumeric, Rng};
+    use sha256::try_digest;
+
+    struct TempDir {
+        path: PathBuf,
+    }
+
+    impl TempDir {
+        pub fn new() -> Self {
+            let s: String = rand::thread_rng()
+                .sample_iter(&Alphanumeric)
+                .take(7)
+                .map(char::from)
+                .collect();
+            let mut path = std::env::temp_dir();
+            path.push(s);
+            std::fs::create_dir(&path).unwrap();
+            Self { path }
+        }
+    }
+
+    impl Drop for TempDir {
+        fn drop(&mut self) {
+            std::fs::remove_dir_all(&self.path).unwrap()
+        }
+    }
+
+    #[tokio::test]
+    async fn simple() {
+        let tmp = TempDir::new();
+        let api = ApiBuilder::new()
+            .with_progress(false)
+            .with_cache_dir(tmp.path.clone())
+            .build()
+            .unwrap();
+        let repo = Repo::new("julien-c/dummy-unknown".to_string(), RepoType::Model);
+        let downloaded_path = api.download(&repo, "config.json").await.unwrap();
+        assert!(downloaded_path.exists());
+        let val = try_digest(&*downloaded_path).unwrap();
+        assert_eq!(
+            val,
+            "b908f2b7227d4d31a2105dfa31095e28d304f9bc938bfaaa57ee2cacf1f62d32"
+        );
+
+        // Make sure the file is now seeable without connection
+        let cache_path = api.cache.get(&repo, "config.json").unwrap();
+        assert_eq!(cache_path, downloaded_path);
+    }
+
+    #[tokio::test]
+    async fn dataset() {
+        let tmp = TempDir::new();
+        let api = ApiBuilder::new()
+            .with_progress(false)
+            .with_cache_dir(tmp.path.clone())
+            .build()
+            .unwrap();
+        let repo = Repo::with_revision(
+            "wikitext".to_string(),
+            RepoType::Dataset,
+            "refs/convert/parquet".to_string(),
+        );
+        let downloaded_path = api
+            .download(&repo, "wikitext-103-v1/wikitext-test.parquet")
+            .await
+            .unwrap();
+        assert!(downloaded_path.exists());
+        let val = try_digest(&*downloaded_path).unwrap();
+        assert_eq!(
+            val,
+            "59ce09415ad8aa45a9e34f88cec2548aeb9de9a73fcda9f6b33a86a065f32b90"
+        )
+    }
+
+    #[tokio::test]
+    async fn info() {
+        let tmp = TempDir::new();
+        let api = ApiBuilder::new()
+            .with_progress(false)
+            .with_cache_dir(tmp.path.clone())
+            .build()
+            .unwrap();
+        let repo = Repo::with_revision(
+            "wikitext".to_string(),
+            RepoType::Dataset,
+            "refs/convert/parquet".to_string(),
+        );
+        let model_info = api.info(&repo).await.unwrap();
+        assert_eq!(
+            model_info,
+            ModelInfo {
+                siblings: vec![
+                    Siblings {
+                        rfilename: ".gitattributes".to_string(),
+                    },
+                    Siblings {
+                        rfilename: "wikitext-103-raw-v1/wikitext-test.parquet".to_string(),
+                    },
+                    Siblings {
+                        rfilename: "wikitext-103-raw-v1/wikitext-train-00000-of-00002.parquet"
+                            .to_string(),
+                    },
+                    Siblings {
+                        rfilename: "wikitext-103-raw-v1/wikitext-train-00001-of-00002.parquet"
+                            .to_string(),
+                    },
+                    Siblings {
+                        rfilename: "wikitext-103-raw-v1/wikitext-validation.parquet".to_string(),
+                    },
+                    Siblings {
+                        rfilename: "wikitext-103-v1/wikitext-test.parquet".to_string(),
+                    },
+                    Siblings {
+                        rfilename: "wikitext-103-v1/wikitext-train-00000-of-00002.parquet"
+                            .to_string(),
+                    },
+                    Siblings {
+                        rfilename: "wikitext-103-v1/wikitext-train-00001-of-00002.parquet"
+                            .to_string(),
+                    },
+                    Siblings {
+                        rfilename: "wikitext-103-v1/wikitext-validation.parquet".to_string(),
+                    },
+                    Siblings {
+                        rfilename: "wikitext-2-raw-v1/wikitext-test.parquet".to_string(),
+                    },
+                    Siblings {
+                        rfilename: "wikitext-2-raw-v1/wikitext-train.parquet".to_string(),
+                    },
+                    Siblings {
+                        rfilename: "wikitext-2-raw-v1/wikitext-validation.parquet".to_string(),
+                    },
+                    Siblings {
+                        rfilename: "wikitext-2-v1/wikitext-test.parquet".to_string(),
+                    },
+                    Siblings {
+                        rfilename: "wikitext-2-v1/wikitext-train.parquet".to_string(),
+                    },
+                    Siblings {
+                        rfilename: "wikitext-2-v1/wikitext-validation.parquet".to_string(),
+                    },
+                ],
+            }
+        )
+    }
+}

candle-hub/src/lib.rs

@@ -0,0 +1,187 @@
+#![deny(missing_docs)]
+//! This crates aims to emulate and be compatible with the
+//! [huggingface_hub](https://github.com/huggingface/huggingface_hub/) python package.
+//!
+//! compatible means the Api should reuse the same files skipping downloads if
+//! they are already present and whenever this crate downloads or modifies this cache
+//! it should be consistent with [huggingface_hub](https://github.com/huggingface/huggingface_hub/)
+//!
+//! At this time only a limited subset of the functionality is present, the goal is to add new
+//! features over time
+use std::io::Write;
+use std::path::PathBuf;
+
+/// The actual Api to interact with the hub.
+#[cfg(feature = "online")]
+pub mod api;
+
+/// The type of repo to interact with
+#[derive(Debug, Clone, Copy)]
+pub enum RepoType {
+    /// This is a model, usually it consists of weight files and some configuration
+    /// files
+    Model,
+    /// This is a dataset, usually contains data within parquet files
+    Dataset,
+    /// This is a space, usually a demo showcashing a given model or dataset
+    Space,
+}
+
+/// A local struct used to fetch information from the cache folder.
+pub struct Cache {
+    path: PathBuf,
+}
+
+impl Cache {
+    /// Creates a new cache object location
+    pub fn new(path: PathBuf) -> Self {
+        Self { path }
+    }
+
+    /// Creates a new cache object location
+    pub fn path(&self) -> &PathBuf {
+        &self.path
+    }
+
+    /// This will get the location of the file within the cache for the remote
+    /// `filename`. Will return `None` if file is not already present in cache.
+    pub fn get(&self, repo: &Repo, filename: &str) -> Option<PathBuf> {
+        let mut commit_path = self.path.clone();
+        commit_path.push(repo.folder_name());
+        commit_path.push("refs");
+        commit_path.push(repo.revision());
+        let commit_hash = std::fs::read_to_string(commit_path).ok()?;
+        let mut pointer_path = self.pointer_path(repo, &commit_hash);
+        pointer_path.push(filename);
+        Some(pointer_path)
+    }
+
+    /// Creates a reference in the cache directory that points branches to the correct
+    /// commits within the blobs.
+    pub fn create_ref(&self, repo: &Repo, commit_hash: &str) -> Result<(), std::io::Error> {
+        let mut ref_path = self.path.clone();
+        ref_path.push(repo.folder_name());
+        ref_path.push("refs");
+        ref_path.push(repo.revision());
+        // Needs to be done like this because revision might contain `/` creating subfolders here.
+        std::fs::create_dir_all(ref_path.parent().unwrap())?;
+        let mut file1 = std::fs::OpenOptions::new()
+            .write(true)
+            .create(true)
+            .open(&ref_path)?;
+        file1.write_all(commit_hash.trim().as_bytes())?;
+        Ok(())
+    }
+
+    #[cfg(feature = "online")]
+    pub(crate) fn blob_path(&self, repo: &Repo, etag: &str) -> PathBuf {
+        let mut blob_path = self.path.clone();
+        blob_path.push(repo.folder_name());
+        blob_path.push("blobs");
+        blob_path.push(etag);
+        blob_path
+    }
+
+    pub(crate) fn pointer_path(&self, repo: &Repo, commit_hash: &str) -> PathBuf {
+        let mut pointer_path = self.path.clone();
+        pointer_path.push(repo.folder_name());
+        pointer_path.push("snapshots");
+        pointer_path.push(commit_hash);
+        pointer_path
+    }
+}
+
+impl Default for Cache {
+    fn default() -> Self {
+        let path = match std::env::var("HF_HOME") {
+            Ok(home) => home.into(),
+            Err(_) => {
+                let mut cache = dirs::home_dir().expect("Cache directory cannot be found");
+                cache.push(".cache");
+                cache.push("huggingface");
+                cache
+            }
+        };
+        Self::new(path)
+    }
+}
+
+/// The representation of a repo on the hub.
+#[allow(dead_code)] // Repo type unused in offline mode
+pub struct Repo {
+    repo_id: String,
+    repo_type: RepoType,
+    revision: String,
+}
+
+impl Repo {
+    /// Repo with the default branch ("main").
+    pub fn new(repo_id: String, repo_type: RepoType) -> Self {
+        Self::with_revision(repo_id, repo_type, "main".to_string())
+    }
+
+    /// fully qualified Repo
+    pub fn with_revision(repo_id: String, repo_type: RepoType, revision: String) -> Self {
+        Self {
+            repo_id,
+            repo_type,
+            revision,
+        }
+    }
+
+    /// Shortcut for [`Repo::new`] with [`RepoType::Model`]
+    pub fn model(repo_id: String) -> Self {
+        Self::new(repo_id, RepoType::Model)
+    }
+
+    /// Shortcut for [`Repo::new`] with [`RepoType::Dataset`]
+    pub fn dataset(repo_id: String) -> Self {
+        Self::new(repo_id, RepoType::Dataset)
+    }
+
+    /// Shortcut for [`Repo::new`] with [`RepoType::Space`]
+    pub fn space(repo_id: String) -> Self {
+        Self::new(repo_id, RepoType::Space)
+    }
+
+    /// The normalized folder nameof the repo within the cache directory
+    pub fn folder_name(&self) -> String {
+        self.repo_id.replace('/', "--")
+    }
+
+    /// The revision
+    pub fn revision(&self) -> &str {
+        &self.revision
+    }
+
+    /// The actual URL part of the repo
+    #[cfg(feature = "online")]
+    pub fn url(&self) -> String {
+        match self.repo_type {
+            RepoType::Model => self.repo_id.to_string(),
+            RepoType::Dataset => {
+                format!("datasets/{}", self.repo_id)
+            }
+            RepoType::Space => {
+                format!("spaces/{}", self.repo_id)
+            }
+        }
+    }
+
+    /// Revision needs to be url escaped before being used in a URL
+    #[cfg(feature = "online")]
+    pub fn url_revision(&self) -> String {
+        self.revision.replace('/', "%2F")
+    }
+
+    /// Used to compute the repo's url part when accessing the metadata of the repo
+    #[cfg(feature = "online")]
+    pub fn api_url(&self) -> String {
+        let prefix = match self.repo_type {
+            RepoType::Model => "models",
+            RepoType::Dataset => "datasets",
+            RepoType::Space => "spaces",
+        };
+        format!("{prefix}/{}/revision/{}", self.repo_id, self.url_revision())
+    }
+}