1 files changed, 260 insertions, 0 deletions
diff --git a/modules/lfs/http_client.go b/modules/lfs/http_client.go
new file mode 100644
index 00000000..7ee2449b
--- /dev/null
+++ b/modules/lfs/http_client.go
@@ -0,0 +1,260 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package lfs
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strings"
+
+	"code.gitea.io/gitea/modules/json"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/proxy"
+)
+
+const httpBatchSize = 20
+
+// HTTPClient is used to communicate with the LFS server
+// https://github.com/git-lfs/git-lfs/blob/main/docs/api/batch.md
+type HTTPClient struct {
+	client    *http.Client
+	endpoint  string
+	transfers map[string]TransferAdapter
+}
+
+// BatchSize returns the preferred size of batchs to process
+func (c *HTTPClient) BatchSize() int {
+	return httpBatchSize
+}
+
+func newHTTPClient(endpoint *url.URL, httpTransport *http.Transport) *HTTPClient {
+	if httpTransport == nil {
+		httpTransport = &http.Transport{
+			Proxy: proxy.Proxy(),
+		}
+	}
+
+	hc := &http.Client{
+		Transport: httpTransport,
+	}
+
+	basic := &BasicTransferAdapter{hc}
+	client := &HTTPClient{
+		client:   hc,
+		endpoint: strings.TrimSuffix(endpoint.String(), "/"),
+		transfers: map[string]TransferAdapter{
+			basic.Name(): basic,
+		},
+	}
+
+	return client
+}
+
+func (c *HTTPClient) transferNames() []string {
+	keys := make([]string, len(c.transfers))
+	i := 0
+	for k := range c.transfers {
+		keys[i] = k
+		i++
+	}
+	return keys
+}
+
+func (c *HTTPClient) batch(ctx context.Context, operation string, objects []Pointer) (*BatchResponse, error) {
+	log.Trace("BATCH operation with objects: %v", objects)
+
+	url := fmt.Sprintf("%s/objects/batch", c.endpoint)
+
+	request := &BatchRequest{operation, c.transferNames(), nil, objects}
+	payload := new(bytes.Buffer)
+	err := json.NewEncoder(payload).Encode(request)
+	if err != nil {
+		log.Error("Error encoding json: %v", err)
+		return nil, err
+	}
+
+	req, err := createRequest(ctx, http.MethodPost, url, map[string]string{"Content-Type": MediaType}, payload)
+	if err != nil {
+		return nil, err
+	}
+
+	res, err := performRequest(ctx, c.client, req)
+	if err != nil {
+		return nil, err
+	}
+	defer res.Body.Close()
+
+	var response BatchResponse
+	err = json.NewDecoder(res.Body).Decode(&response)
+	if err != nil {
+		log.Error("Error decoding json: %v", err)
+		return nil, err
+	}
+
+	if len(response.Transfer) == 0 {
+		response.Transfer = "basic"
+	}
+
+	return &response, nil
+}
+
+// Download reads the specific LFS object from the LFS server
+func (c *HTTPClient) Download(ctx context.Context, objects []Pointer, callback DownloadCallback) error {
+	return c.performOperation(ctx, objects, callback, nil)
+}
+
+// Upload sends the specific LFS object to the LFS server
+func (c *HTTPClient) Upload(ctx context.Context, objects []Pointer, callback UploadCallback) error {
+	return c.performOperation(ctx, objects, nil, callback)
+}
+
+func (c *HTTPClient) performOperation(ctx context.Context, objects []Pointer, dc DownloadCallback, uc UploadCallback) error {
+	if len(objects) == 0 {
+		return nil
+	}
+
+	operation := "download"
+	if uc != nil {
+		operation = "upload"
+	}
+
+	result, err := c.batch(ctx, operation, objects)
+	if err != nil {
+		return err
+	}
+
+	transferAdapter, ok := c.transfers[result.Transfer]
+	if !ok {
+		return fmt.Errorf("TransferAdapter not found: %s", result.Transfer)
+	}
+
+	for _, object := range result.Objects {
+		if object.Error != nil {
+			objectError := errors.New(object.Error.Message)
+			log.Trace("Error on object %v: %v", object.Pointer, objectError)
+			if uc != nil {
+				if _, err := uc(object.Pointer, objectError); err != nil {
+					return err
+				}
+			} else {
+				if err := dc(object.Pointer, nil, objectError); err != nil {
+					return err
+				}
+			}
+			continue
+		}
+
+		if uc != nil {
+			if len(object.Actions) == 0 {
+				log.Trace("%v already present on server", object.Pointer)
+				continue
+			}
+
+			link, ok := object.Actions["upload"]
+			if !ok {
+				log.Debug("%+v", object)
+				return errors.New("missing action 'upload'")
+			}
+
+			content, err := uc(object.Pointer, nil)
+			if err != nil {
+				return err
+			}
+
+			err = transferAdapter.Upload(ctx, link, object.Pointer, content)
+			if err != nil {
+				return err
+			}
+
+			link, ok = object.Actions["verify"]
+			if ok {
+				if err := transferAdapter.Verify(ctx, link, object.Pointer); err != nil {
+					return err
+				}
+			}
+		} else {
+			link, ok := object.Actions["download"]
+			if !ok {
+				// no actions block in response, try legacy response schema
+				link, ok = object.Links["download"]
+			}
+			if !ok {
+				log.Debug("%+v", object)
+				return errors.New("missing action 'download'")
+			}
+
+			content, err := transferAdapter.Download(ctx, link)
+			if err != nil {
+				return err
+			}
+
+			if err := dc(object.Pointer, content, nil); err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}
+
+// createRequest creates a new request, and sets the headers.
+func createRequest(ctx context.Context, method, url string, headers map[string]string, body io.Reader) (*http.Request, error) {
+	log.Trace("createRequest: %s", url)
+	req, err := http.NewRequestWithContext(ctx, method, url, body)
+	if err != nil {
+		log.Error("Error creating request: %v", err)
+		return nil, err
+	}
+
+	for key, value := range headers {
+		req.Header.Set(key, value)
+	}
+	req.Header.Set("Accept", AcceptHeader)
+
+	return req, nil
+}
+
+// performRequest sends a request, optionally performs a callback on the request and returns the response.
+// If the status code is 200, the response is returned, and it will contain a non-nil Body.
+// Otherwise, it will return an error, and the Body will be nil or closed.
+func performRequest(ctx context.Context, client *http.Client, req *http.Request) (*http.Response, error) {
+	log.Trace("performRequest: %s", req.URL)
+	res, err := client.Do(req)
+	if err != nil {
+		select {
+		case <-ctx.Done():
+			return res, ctx.Err()
+		default:
+		}
+		log.Error("Error while processing request: %v", err)
+		return res, err
+	}
+
+	if res.StatusCode != http.StatusOK {
+		defer res.Body.Close()
+		return res, handleErrorResponse(res)
+	}
+
+	return res, nil
+}
+
+func handleErrorResponse(resp *http.Response) error {
+	var er ErrorResponse
+	err := json.NewDecoder(resp.Body).Decode(&er)
+	if err != nil {
+		if err == io.EOF {
+			return io.ErrUnexpectedEOF
+		}
+		log.Error("Error decoding json: %v", err)
+		return err
+	}
+
+	log.Trace("ErrorResponse(%v): %v", resp.Status, er)
+	return errors.New(er.Message)
+}