// 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" 	"forgejo.org/modules/json"	"forgejo.org/modules/log"	"forgejo.org/modules/proxy"	"forgejo.org/modules/setting" 	"golang.org/x/sync/errgroup") // HTTPClient is used to communicate with the LFS server// https://github.com/git-lfs/git-lfs/blob/main/docs/api/batch.mdtype HTTPClient struct {	client    *http.Client	endpoint  string	transfers map[string]TransferAdapter} // BatchSize returns the preferred size of batchs to processfunc (c *HTTPClient) BatchSize() int {	return setting.LFSClient.BatchSize} 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) 	// Original:  In some lfs server implementations, they require the ref attribute. #32838	// `ref` is an "optional object describing the server ref that the objects belong to"	// but some (incorrect) lfs servers like aliyun require it, so maybe adding an empty ref here doesn't break the correct ones.	// https://github.com/git-lfs/git-lfs/blob/a32a02b44bf8a511aa14f047627c49e1a7fd5021/docs/api/batch.md?plain=1#L37	//	// UPDATE: it can't use "empty ref" here because it breaks others like https://github.com/go-gitea/gitea/issues/33453	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 serverfunc (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 serverfunc (c *HTTPClient) Upload(ctx context.Context, objects []Pointer, callback UploadCallback) error {	return c.performOperation(ctx, objects, nil, callback)} // performOperation takes a slice of LFS object pointers, batches them, and performs the upload/download operations concurrently in each batchfunc (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)	} 	if setting.LFSClient.BatchOperationConcurrency <= 0 {		panic("BatchOperationConcurrency must be greater than 0, forgot to init?")	}	errGroup, groupCtx := errgroup.WithContext(ctx)	errGroup.SetLimit(setting.LFSClient.BatchOperationConcurrency)	for _, object := range result.Objects {		errGroup.Go(func() error {			return performSingleOperation(groupCtx, object, dc, uc, transferAdapter)		})	} 	// only the first error is returned, preserving legacy behavior before concurrency	return errGroup.Wait()} // performSingleOperation performs an LFS upload or download operation on a single objectfunc performSingleOperation(ctx context.Context, object *ObjectResponse, dc DownloadCallback, uc UploadCallback, transferAdapter TransferAdapter) error {	// the response from a lfs batch api request for this specific object id contained an error	if object.Error != nil {		log.Trace("Error on object %v: %v", object.Pointer, object.Error) 		// this was an 'upload' request inside the batch request		if uc != nil {			if _, err := uc(object.Pointer, object.Error); err != nil {				return err			}		} else {			// this was NOT an 'upload' request inside the batch request, meaning it must be a 'download' request			if err := dc(object.Pointer, nil, object.Error); err != nil {				return err			}		}		// if the callback returns no err, then the error could be ignored, and the operations should continue		return nil	} 	// the response from an lfs batch api request contained necessary upload/download fields to act upon	if uc != nil {		if len(object.Actions) == 0 {			log.Trace("%v already present on server", object.Pointer)			return nil		} 		link, ok := object.Actions["upload"]		if !ok {			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)	req.Header.Set("User-Agent", UserAgentHeader) 	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)}