github.com/mattermosttest/mattermost-server/v5@v5.0.0-20200917143240-9dfa12e121f9/app/download.go (about)

     1  // Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
     2  // See LICENSE.txt for license information.
     3  
     4  package app
     5  
     6  import (
     7  	"io"
     8  	"io/ioutil"
     9  	"net/http"
    10  	"net/url"
    11  	"time"
    12  
    13  	"github.com/mattermost/mattermost-server/v5/model"
    14  	"github.com/mattermost/mattermost-server/v5/utils"
    15  
    16  	"github.com/pkg/errors"
    17  )
    18  
    19  const (
    20  	// HTTP_REQUEST_TIMEOUT defines a high timeout for downloading large files
    21  	// from an external URL to avoid slow connections from failing to install.
    22  	HTTP_REQUEST_TIMEOUT = 1 * time.Hour
    23  )
    24  
    25  func (a *App) DownloadFromURL(downloadURL string) ([]byte, error) {
    26  	if !model.IsValidHttpUrl(downloadURL) {
    27  		return nil, errors.Errorf("invalid url %s", downloadURL)
    28  	}
    29  
    30  	u, err := url.ParseRequestURI(downloadURL)
    31  	if err != nil {
    32  		return nil, errors.Errorf("failed to parse url %s", downloadURL)
    33  	}
    34  	if !*a.Config().PluginSettings.AllowInsecureDownloadUrl && u.Scheme != "https" {
    35  		return nil, errors.Errorf("insecure url not allowed %s", downloadURL)
    36  	}
    37  
    38  	client := a.HTTPService().MakeClient(true)
    39  	client.Timeout = HTTP_REQUEST_TIMEOUT
    40  
    41  	var resp *http.Response
    42  	err = utils.ProgressiveRetry(func() error {
    43  		resp, err = client.Get(downloadURL)
    44  
    45  		if err != nil {
    46  			return errors.Wrapf(err, "failed to fetch from %s", downloadURL)
    47  		}
    48  
    49  		if !(resp.StatusCode >= 200 && resp.StatusCode < 300) {
    50  			_, _ = io.Copy(ioutil.Discard, resp.Body)
    51  			_ = resp.Body.Close()
    52  			return errors.Errorf("failed to fetch from %s", downloadURL)
    53  		}
    54  
    55  		return nil
    56  	})
    57  	if err != nil {
    58  		return nil, errors.Wrap(err, "download failed after multiple retries.")
    59  	}
    60  
    61  	defer resp.Body.Close()
    62  
    63  	return ioutil.ReadAll(resp.Body)
    64  }