github.com/euank/go@v0.0.0-20160829210321-495514729181/src/cmd/go/http.go (about)

     1  // Copyright 2012 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // +build !cmd_go_bootstrap
     6  
     7  // This code is compiled into the real 'go' binary, but it is not
     8  // compiled into the binary that is built during all.bash, so as
     9  // to avoid needing to build net (and thus use cgo) during the
    10  // bootstrap process.
    11  
    12  package main
    13  
    14  import (
    15  	"crypto/tls"
    16  	"fmt"
    17  	"io"
    18  	"io/ioutil"
    19  	"log"
    20  	"net/http"
    21  	"net/url"
    22  	"time"
    23  )
    24  
    25  // httpClient is the default HTTP client, but a variable so it can be
    26  // changed by tests, without modifying http.DefaultClient.
    27  var httpClient = http.DefaultClient
    28  
    29  // impatientInsecureHTTPClient is used in -insecure mode,
    30  // when we're connecting to https servers that might not be there
    31  // or might be using self-signed certificates.
    32  var impatientInsecureHTTPClient = &http.Client{
    33  	Timeout: 5 * time.Second,
    34  	Transport: &http.Transport{
    35  		TLSClientConfig: &tls.Config{
    36  			InsecureSkipVerify: true,
    37  		},
    38  	},
    39  }
    40  
    41  type httpError struct {
    42  	status     string
    43  	statusCode int
    44  	url        string
    45  }
    46  
    47  func (e *httpError) Error() string {
    48  	return fmt.Sprintf("%s: %s", e.url, e.status)
    49  }
    50  
    51  // httpGET returns the data from an HTTP GET request for the given URL.
    52  func httpGET(url string) ([]byte, error) {
    53  	resp, err := httpClient.Get(url)
    54  	if err != nil {
    55  		return nil, err
    56  	}
    57  	defer resp.Body.Close()
    58  	if resp.StatusCode != 200 {
    59  		err := &httpError{status: resp.Status, statusCode: resp.StatusCode, url: url}
    60  
    61  		return nil, err
    62  	}
    63  	b, err := ioutil.ReadAll(resp.Body)
    64  	if err != nil {
    65  		return nil, fmt.Errorf("%s: %v", url, err)
    66  	}
    67  	return b, nil
    68  }
    69  
    70  // httpsOrHTTP returns the body of either the importPath's
    71  // https resource or, if unavailable, the http resource.
    72  func httpsOrHTTP(importPath string, security securityMode) (urlStr string, body io.ReadCloser, err error) {
    73  	fetch := func(scheme string) (urlStr string, res *http.Response, err error) {
    74  		u, err := url.Parse(scheme + "://" + importPath)
    75  		if err != nil {
    76  			return "", nil, err
    77  		}
    78  		u.RawQuery = "go-get=1"
    79  		urlStr = u.String()
    80  		if buildV {
    81  			log.Printf("Fetching %s", urlStr)
    82  		}
    83  		if security == insecure && scheme == "https" { // fail earlier
    84  			res, err = impatientInsecureHTTPClient.Get(urlStr)
    85  		} else {
    86  			res, err = httpClient.Get(urlStr)
    87  		}
    88  		return
    89  	}
    90  	closeBody := func(res *http.Response) {
    91  		if res != nil {
    92  			res.Body.Close()
    93  		}
    94  	}
    95  	urlStr, res, err := fetch("https")
    96  	if err != nil {
    97  		if buildV {
    98  			log.Printf("https fetch failed: %v", err)
    99  		}
   100  		if security == insecure {
   101  			closeBody(res)
   102  			urlStr, res, err = fetch("http")
   103  		}
   104  	}
   105  	if err != nil {
   106  		closeBody(res)
   107  		return "", nil, err
   108  	}
   109  	// Note: accepting a non-200 OK here, so people can serve a
   110  	// meta import in their http 404 page.
   111  	if buildV {
   112  		log.Printf("Parsing meta tags from %s (status code %d)", urlStr, res.StatusCode)
   113  	}
   114  	return urlStr, res.Body, nil
   115  }