git-lfs-api 0.2.0

//! Batch API: request the ability to transfer LFS objects.
//!
//! See `docs/api/batch.md` for the wire-protocol contract.

use std::collections::HashMap;

use serde::{Deserialize, Serialize};

use crate::client::Client;
use crate::error::ApiError;
use crate::models::Ref;

/// Operation requested from the batch endpoint.
#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
#[serde(rename_all = "lowercase")]
pub enum Operation {
    Download,
    Upload,
}

/// One object the client wants to transfer.
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
pub struct ObjectSpec {
    pub oid: String,
    pub size: u64,
}

/// A POST body for `/objects/batch`.
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
pub struct BatchRequest {
    pub operation: Operation,
    /// Transfer adapter identifiers the client supports. If empty, the spec
    /// says the server MUST assume `basic`. We send the field unconditionally
    /// so the server's preferred adapter is well-defined.
    #[serde(default, skip_serializing_if = "Vec::is_empty")]
    pub transfers: Vec<String>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub r#ref: Option<Ref>,
    pub objects: Vec<ObjectSpec>,
    /// Optional hash algorithm. Defaults to `sha256` per the spec.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub hash_algo: Option<String>,
}

impl BatchRequest {
    pub fn new(operation: Operation, objects: Vec<ObjectSpec>) -> Self {
        Self {
            operation,
            transfers: Vec::new(),
            r#ref: None,
            objects,
            hash_algo: None,
        }
    }

    pub fn with_transfers(mut self, transfers: impl IntoIterator<Item = String>) -> Self {
        self.transfers = transfers.into_iter().collect();
        self
    }

    pub fn with_ref(mut self, r: Ref) -> Self {
        self.r#ref = Some(r);
        self
    }
}

/// Response body from `/objects/batch`.
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
pub struct BatchResponse {
    /// Transfer adapter the server picked. `None` means the server omitted
    /// it; per the spec the client should assume `basic`.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub transfer: Option<String>,
    pub objects: Vec<ObjectResult>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub hash_algo: Option<String>,
}

/// Per-object result inside a batch response. Either `actions` or `error`
/// is populated; both being absent means "server already has this object"
/// (an upload no-op).
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
pub struct ObjectResult {
    pub oid: String,
    /// Size in bytes. Per the spec this is required, but the upstream
    /// `lfstest-gitserver` (and at least one production server in the
    /// wild) omit it on the action path — they assume the client
    /// already knows. Default to 0 so we don't refuse the response;
    /// callers that need the real size should look it up from the
    /// matching request entry.
    #[serde(default)]
    pub size: u64,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub authenticated: Option<bool>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub actions: Option<Actions>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub error: Option<ObjectError>,
}

/// Per-object error inside a batch response.
///
/// Codes mirror HTTP status codes per `docs/api/batch.md`:
/// 404 = not found, 409 = hash-algo mismatch, 410 = removed, 422 = invalid.
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
pub struct ObjectError {
    pub code: u32,
    pub message: String,
}

/// The set of next-step actions the server returned for one object.
///
/// Field set depends on `operation`: `download` populates `download`;
/// `upload` populates `upload` and optionally `verify`.
#[derive(Debug, Clone, Default, Serialize, Deserialize, PartialEq, Eq)]
pub struct Actions {
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub download: Option<Action>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub upload: Option<Action>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub verify: Option<Action>,
}

/// One concrete HTTP request the transfer adapter should make.
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
pub struct Action {
    pub href: String,
    #[serde(default, skip_serializing_if = "HashMap::is_empty")]
    pub header: HashMap<String, String>,
    /// Seconds until the action URL stops being valid. Preferred over
    /// `expires_at` when both are given. Per the spec, range is roughly
    /// ±2^31 seconds.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub expires_in: Option<i64>,
    /// Absolute uppercase RFC 3339 timestamp at which the action URL stops
    /// being valid. Carried as a string — see [`Lock`](crate::Lock).
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub expires_at: Option<String>,
}

impl Client {
    /// POST `/objects/batch` to negotiate transfer URLs.
    pub async fn batch(&self, req: &BatchRequest) -> Result<BatchResponse, ApiError> {
        self.post_json("objects/batch", req).await
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn operation_serializes_lowercase() {
        let s = serde_json::to_string(&Operation::Download).unwrap();
        assert_eq!(s, "\"download\"");
    }

    #[test]
    fn request_skips_empty_optional_fields() {
        let req = BatchRequest::new(
            Operation::Download,
            vec![ObjectSpec { oid: "abc".into(), size: 10 }],
        );
        let v = serde_json::to_value(&req).unwrap();
        assert!(v.get("transfers").is_none());
        assert!(v.get("ref").is_none());
        assert!(v.get("hash_algo").is_none());
    }

    #[test]
    fn parses_canonical_download_response() {
        let body = r#"{
            "transfer": "basic",
            "objects": [{
                "oid": "1111111",
                "size": 123,
                "authenticated": true,
                "actions": {
                    "download": {
                        "href": "https://some-download.com",
                        "header": { "Key": "value" },
                        "expires_at": "2016-11-10T15:29:07Z"
                    }
                }
            }],
            "hash_algo": "sha256"
        }"#;
        let resp: BatchResponse = serde_json::from_str(body).unwrap();
        assert_eq!(resp.transfer.as_deref(), Some("basic"));
        let obj = &resp.objects[0];
        assert_eq!(obj.authenticated, Some(true));
        let action = obj.actions.as_ref().unwrap().download.as_ref().unwrap();
        assert_eq!(action.href, "https://some-download.com");
        assert_eq!(action.header.get("Key").unwrap(), "value");
        assert!(action.expires_in.is_none());
    }

    #[test]
    fn parses_per_object_error() {
        let body = r#"{
            "transfer": "basic",
            "objects": [{
                "oid": "1111111", "size": 123,
                "error": { "code": 404, "message": "Object does not exist" }
            }]
        }"#;
        let resp: BatchResponse = serde_json::from_str(body).unwrap();
        let err = resp.objects[0].error.as_ref().unwrap();
        assert_eq!(err.code, 404);
        assert_eq!(err.message, "Object does not exist");
    }

    #[test]
    fn parses_upload_already_present_no_actions() {
        let body = r#"{
            "objects": [{ "oid": "1111111", "size": 123 }]
        }"#;
        let resp: BatchResponse = serde_json::from_str(body).unwrap();
        let obj = &resp.objects[0];
        assert!(obj.actions.is_none());
        assert!(obj.error.is_none());
    }
}