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package httpclient
import (
"bytes"
"encoding/json"
"encoding/xml"
"fmt"
"io"
"io/ioutil"
"net/http"
"net/http/httputil"
"net/url"
"os"
"strings"
"time"
)
var XmlHeaderBytes []byte = []byte(xml.Header)
type ErrorHandlerFunc func(*http.Response, error) error
type PostHookFunc func(*http.Request, *http.Response) error
type HTTPClient struct {
BaseURL *url.URL
Headers http.Header
Client *http.Client
PostHooks map[int]PostHookFunc
errorHandler ErrorHandlerFunc
rateLimited bool
rateLimitChan chan struct{}
rateLimitTimeout time.Duration
}
func New() (httpClient *HTTPClient) {
return &HTTPClient{
Client: HttpClient,
Headers: make(http.Header),
PostHooks: make(map[int]PostHookFunc),
}
}
func Insecure() (httpClient *HTTPClient) {
httpClient = New()
httpClient.Client = InsecureHttpClient
return httpClient
}
var DefaultClient = New()
func (c *HTTPClient) SetPostHook(onStatus int, hook PostHookFunc) {
c.PostHooks[onStatus] = hook
}
func (c *HTTPClient) SetErrorHandler(handler ErrorHandlerFunc) {
c.errorHandler = handler
}
func (c *HTTPClient) SetRateLimit(limit int, timeout time.Duration) {
c.rateLimited = true
c.rateLimitChan = make(chan struct{}, limit)
for i := 0; i < limit; i++ {
c.rateLimitChan <- struct{}{}
}
c.rateLimitTimeout = timeout
}
func (c *HTTPClient) buildURL(req *RequestData) *url.URL {
bu := c.BaseURL
rpath := req.Path
if strings.HasSuffix(bu.Path, "/") && strings.HasPrefix(rpath, "/") {
rpath = rpath[1:]
}
opaque := EscapePath(bu.Path + rpath)
u := &url.URL{
Scheme: bu.Scheme,
Host: bu.Host,
Opaque: opaque,
}
if req.Params != nil {
u.RawQuery = req.Params.Encode()
}
return u
}
func (c *HTTPClient) setHeaders(req *RequestData, httpReq *http.Request) {
switch req.RespEncoding {
case EncodingJSON:
httpReq.Header.Set("Accept", "application/json")
case EncodingXML:
httpReq.Header.Set("Accept", "application/xml")
}
if c.Headers != nil {
for key, values := range c.Headers {
for _, value := range values {
httpReq.Header.Set(key, value)
}
}
}
if req.Headers != nil {
for key, values := range req.Headers {
for _, value := range values {
httpReq.Header.Set(key, value)
}
}
}
}
func (c *HTTPClient) checkStatus(req *RequestData, response *http.Response) (err error) {
if req.ExpectedStatus != nil {
statusOk := false
for _, status := range req.ExpectedStatus {
if response.StatusCode == status {
statusOk = true
}
}
if !statusOk {
lr := io.LimitReader(response.Body, 10*1024)
contentBytes, _ := ioutil.ReadAll(lr)
content := string(contentBytes)
err = InvalidStatusError{
Expected: req.ExpectedStatus,
Got: response.StatusCode,
Headers: response.Header,
Content: content,
}
return err
}
}
return nil
}
func (c *HTTPClient) unmarshalResponse(req *RequestData, response *http.Response) (err error) {
var buf []byte
switch req.RespEncoding {
case EncodingJSON:
defer response.Body.Close()
if buf, err = ioutil.ReadAll(response.Body); err != nil {
return err
}
err = json.Unmarshal(buf, req.RespValue)
if err != nil {
return err
}
return nil
case EncodingXML:
defer response.Body.Close()
if buf, err = ioutil.ReadAll(response.Body); err != nil {
return err
}
err = xml.Unmarshal(buf, req.RespValue)
if err != nil {
return err
}
return nil
}
switch req.RespValue.(type) {
case *[]byte:
defer response.Body.Close()
if buf, err = ioutil.ReadAll(response.Body); err != nil {
return err
}
respVal := req.RespValue.(*[]byte)
*respVal = buf
return nil
}
if req.RespConsume {
defer response.Body.Close()
ioutil.ReadAll(response.Body)
}
return nil
}
func (c *HTTPClient) marshalRequest(req *RequestData) (err error) {
if req.ReqReader != nil || req.ReqValue == nil {
return nil
}
if req.Headers == nil {
req.Headers = make(http.Header)
}
var buf []byte
switch req.ReqEncoding {
case EncodingJSON:
buf, err = json.Marshal(req.ReqValue)
if err != nil {
return err
}
req.ReqReader = bytes.NewReader(buf)
req.Headers.Set("Content-Type", "application/json")
req.Headers.Set("Content-Length", fmt.Sprintf("%d", len(buf)))
req.ReqContentLength = int64(len(buf))
return nil
case EncodingXML:
buf, err = xml.Marshal(req.ReqValue)
if err != nil {
return err
}
buf = append(XmlHeaderBytes, buf...)
req.ReqReader = bytes.NewReader(buf)
req.Headers.Set("Content-Type", "application/xml")
req.Headers.Set("Content-Length", fmt.Sprintf("%d", len(buf)))
req.ReqContentLength = int64(len(buf))
return nil
case EncodingForm:
if data, ok := req.ReqValue.(url.Values); ok {
formStr := data.Encode()
req.ReqReader = strings.NewReader(formStr)
req.Headers.Set("Content-Type", "application/x-www-form-urlencoded")
req.Headers.Set("Content-Length", fmt.Sprintf("%d", len(formStr)))
req.ReqContentLength = int64(len(formStr))
return nil
} else {
return fmt.Errorf("HTTPClient: invalid ReqValue type %T", req.ReqValue)
}
}
return fmt.Errorf("HTTPClient: invalid ReqEncoding: %s", req.ReqEncoding)
}
func (c *HTTPClient) runPostHook(req *http.Request, response *http.Response) (err error) {
hook, ok := c.PostHooks[response.StatusCode]
if ok {
err = hook(req, response)
}
return err
}
func (c *HTTPClient) Request(req *RequestData) (response *http.Response, err error) {
err = c.marshalRequest(req)
if err != nil {
return nil, err
}
r, err := http.NewRequest(req.Method, req.FullURL, req.ReqReader)
if err != nil {
return nil, err
}
if req.Context != nil {
r = r.WithContext(req.Context)
}
r.ContentLength = req.ReqContentLength
if req.FullURL == "" {
r.URL = c.buildURL(req)
r.Host = r.URL.Host
}
c.setHeaders(req, r)
if c.rateLimited {
if c.rateLimitTimeout > 0 {
select {
case t := <-c.rateLimitChan:
defer func() {
c.rateLimitChan <- t
}()
case <-time.After(c.rateLimitTimeout):
return nil, RateLimitTimeoutError
}
} else {
t := <-c.rateLimitChan
defer func() {
c.rateLimitChan <- t
}()
}
}
isTraceEnabled := os.Getenv("HTTPCLIENT_TRACE") != ""
if isTraceEnabled {
requestBytes, _ := httputil.DumpRequestOut(r, true)
fmt.Println(string(requestBytes))
}
if req.IgnoreRedirects {
transport := c.Client.Transport
if transport == nil {
transport = http.DefaultTransport
}
response, err = transport.RoundTrip(r)
} else {
response, err = c.Client.Do(r)
}
if err != nil {
if req.Context != nil {
// If we got an error, and the context has been canceled,
// the context's error is probably more useful.
select {
case <-req.Context.Done():
err = req.Context.Err()
default:
}
}
if c.errorHandler != nil {
err = c.errorHandler(response, err)
}
return nil, err
}
if isTraceEnabled {
responseBytes, _ := httputil.DumpResponse(response, true)
fmt.Println(string(responseBytes))
}
if err = c.runPostHook(r, response); err != nil {
return response, err
}
if err = c.checkStatus(req, response); err != nil {
defer response.Body.Close()
return response, err
}
if err = c.unmarshalResponse(req, response); err != nil {
return response, err
}
return response, nil
}
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