lego/acme/http.go

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package acme
import (
"crypto/tls"
"crypto/x509"
"encoding/json"
"errors"
"fmt"
"io"
"io/ioutil"
"net"
"net/http"
"os"
"runtime"
"strings"
"time"
)
var (
// UserAgent (if non-empty) will be tacked onto the User-Agent string in requests.
UserAgent string
// HTTPClient is an HTTP client with a reasonable timeout value and
// potentially a custom *x509.CertPool based on the caCertificatesEnvVar
// environment variable (see the `initCertPool` function)
HTTPClient = http.Client{
Transport: &http.Transport{
Proxy: http.ProxyFromEnvironment,
DialContext: (&net.Dialer{
Timeout: 30 * time.Second,
KeepAlive: 30 * time.Second,
}).DialContext,
TLSHandshakeTimeout: 15 * time.Second,
ResponseHeaderTimeout: 15 * time.Second,
ExpectContinueTimeout: 1 * time.Second,
TLSClientConfig: &tls.Config{
RootCAs: initCertPool(),
},
},
}
)
const (
// defaultGoUserAgent is the Go HTTP package user agent string. Too
// bad it isn't exported. If it changes, we should update it here, too.
defaultGoUserAgent = "Go-http-client/1.1"
// ourUserAgent is the User-Agent of this underlying library package.
ourUserAgent = "xenolf-acme"
// caCertificatesEnvVar is the environment variable name that can be used to
// specify the path to PEM encoded CA Certificates that can be used to
// authenticate an ACME server with a HTTPS certificate not issued by a CA in
// the system-wide trusted root list.
caCertificatesEnvVar = "LEGO_CA_CERTIFICATES"
)
// initCertPool creates a *x509.CertPool populated with the PEM certificates
// found in the filepath specified in the caCertificatesEnvVar OS environment
// variable. If the caCertificatesEnvVar is not set then initCertPool will
// return nil. If there is an error creating a *x509.CertPool from the provided
// caCertificatesEnvVar value then initCertPool will panic.
func initCertPool() *x509.CertPool {
if customCACertsPath := os.Getenv(caCertificatesEnvVar); customCACertsPath != "" {
customCAs, err := ioutil.ReadFile(customCACertsPath)
if err != nil {
panic(fmt.Sprintf("error reading %s=%q: %v",
caCertificatesEnvVar, customCACertsPath, err))
}
certPool := x509.NewCertPool()
if ok := certPool.AppendCertsFromPEM(customCAs); !ok {
panic(fmt.Sprintf("error creating x509 cert pool from %s=%q: %v",
caCertificatesEnvVar, customCACertsPath, err))
}
return certPool
}
return nil
}
// httpHead performs a HEAD request with a proper User-Agent string.
// The response body (resp.Body) is already closed when this function returns.
func httpHead(url string) (resp *http.Response, err error) {
req, err := http.NewRequest(http.MethodHead, url, nil)
if err != nil {
return nil, fmt.Errorf("failed to head %q: %v", url, err)
}
req.Header.Set("User-Agent", userAgent())
resp, err = HTTPClient.Do(req)
if err != nil {
return resp, fmt.Errorf("failed to do head %q: %v", url, err)
}
resp.Body.Close()
return resp, err
}
// httpPost performs a POST request with a proper User-Agent string.
// Callers should close resp.Body when done reading from it.
func httpPost(url string, bodyType string, body io.Reader) (resp *http.Response, err error) {
req, err := http.NewRequest(http.MethodPost, url, body)
if err != nil {
return nil, fmt.Errorf("failed to post %q: %v", url, err)
}
req.Header.Set("Content-Type", bodyType)
req.Header.Set("User-Agent", userAgent())
return HTTPClient.Do(req)
}
// httpGet performs a GET request with a proper User-Agent string.
// Callers should close resp.Body when done reading from it.
func httpGet(url string) (resp *http.Response, err error) {
req, err := http.NewRequest(http.MethodGet, url, nil)
if err != nil {
return nil, fmt.Errorf("failed to get %q: %v", url, err)
}
req.Header.Set("User-Agent", userAgent())
return HTTPClient.Do(req)
}
// getJSON performs an HTTP GET request and parses the response body
// as JSON, into the provided respBody object.
func getJSON(uri string, respBody interface{}) (http.Header, error) {
resp, err := httpGet(uri)
if err != nil {
return nil, fmt.Errorf("failed to get json %q: %v", uri, err)
}
defer resp.Body.Close()
if resp.StatusCode >= http.StatusBadRequest {
return resp.Header, handleHTTPError(resp)
}
return resp.Header, json.NewDecoder(resp.Body).Decode(respBody)
}
// postJSON performs an HTTP POST request and parses the response body
// as JSON, into the provided respBody object.
func postJSON(j *jws, uri string, reqBody, respBody interface{}) (http.Header, error) {
jsonBytes, err := json.Marshal(reqBody)
if err != nil {
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return nil, errors.New("Failed to marshal network message")
}
resp, err := j.post(uri, jsonBytes)
if err != nil {
return nil, fmt.Errorf("Failed to post JWS message. -> %v", err)
}
defer resp.Body.Close()
if resp.StatusCode >= http.StatusBadRequest {
err := handleHTTPError(resp)
switch err.(type) {
case NonceError:
// Retry once if the nonce was invalidated
retryResp, err := j.post(uri, jsonBytes)
if err != nil {
return nil, fmt.Errorf("Failed to post JWS message. -> %v", err)
}
defer retryResp.Body.Close()
if retryResp.StatusCode >= http.StatusBadRequest {
return retryResp.Header, handleHTTPError(retryResp)
}
if respBody == nil {
return retryResp.Header, nil
}
return retryResp.Header, json.NewDecoder(retryResp.Body).Decode(respBody)
default:
return resp.Header, err
}
}
if respBody == nil {
return resp.Header, nil
}
return resp.Header, json.NewDecoder(resp.Body).Decode(respBody)
}
// userAgent builds and returns the User-Agent string to use in requests.
func userAgent() string {
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ua := fmt.Sprintf("%s %s (%s; %s) %s", UserAgent, ourUserAgent, runtime.GOOS, runtime.GOARCH, defaultGoUserAgent)
return strings.TrimSpace(ua)
}