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matterbridge/vendor/github.com/slack-go/slack/misc.go
2020-10-11 23:07:00 +02:00

362 lines
8.4 KiB
Go

package slack
import (
"bytes"
"context"
"encoding/json"
"errors"
"fmt"
"io"
"io/ioutil"
"mime"
"mime/multipart"
"net/http"
"net/http/httputil"
"net/url"
"os"
"path/filepath"
"strconv"
"strings"
"time"
)
// SlackResponse handles parsing out errors from the web api.
type SlackResponse struct {
Ok bool `json:"ok"`
Error string `json:"error"`
ResponseMetadata ResponseMetadata `json:"response_metadata"`
}
func (t SlackResponse) Err() error {
if t.Ok {
return nil
}
// handle pure text based responses like chat.post
// which while they have a slack response in their data structure
// it doesn't actually get set during parsing.
if strings.TrimSpace(t.Error) == "" {
return nil
}
return errors.New(t.Error)
}
// StatusCodeError represents an http response error.
// type httpStatusCode interface { HTTPStatusCode() int } to handle it.
type statusCodeError struct {
Code int
Status string
}
func (t statusCodeError) Error() string {
return fmt.Sprintf("slack server error: %s", t.Status)
}
func (t statusCodeError) HTTPStatusCode() int {
return t.Code
}
func (t statusCodeError) Retryable() bool {
if t.Code >= 500 || t.Code == http.StatusTooManyRequests {
return true
}
return false
}
// RateLimitedError represents the rate limit respond from slack
type RateLimitedError struct {
RetryAfter time.Duration
}
func (e *RateLimitedError) Error() string {
return fmt.Sprintf("slack rate limit exceeded, retry after %s", e.RetryAfter)
}
func (e *RateLimitedError) Retryable() bool {
return true
}
func fileUploadReq(ctx context.Context, path string, values url.Values, r io.Reader) (*http.Request, error) {
req, err := http.NewRequest("POST", path, r)
if err != nil {
return nil, err
}
req = req.WithContext(ctx)
req.URL.RawQuery = (values).Encode()
return req, nil
}
func downloadFile(client httpClient, token string, downloadURL string, writer io.Writer, d debug) error {
if downloadURL == "" {
return fmt.Errorf("received empty download URL")
}
req, err := http.NewRequest("GET", downloadURL, &bytes.Buffer{})
if err != nil {
return err
}
var bearer = "Bearer " + token
req.Header.Add("Authorization", bearer)
req.WithContext(context.Background())
resp, err := client.Do(req)
if err != nil {
return err
}
defer resp.Body.Close()
err = checkStatusCode(resp, d)
if err != nil {
return err
}
_, err = io.Copy(writer, resp.Body)
return err
}
func formReq(endpoint string, values url.Values) (req *http.Request, err error) {
if req, err = http.NewRequest("POST", endpoint, strings.NewReader(values.Encode())); err != nil {
return nil, err
}
req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
return req, nil
}
func jsonReq(endpoint string, body interface{}) (req *http.Request, err error) {
buffer := bytes.NewBuffer([]byte{})
if err = json.NewEncoder(buffer).Encode(body); err != nil {
return nil, err
}
if req, err = http.NewRequest("POST", endpoint, buffer); err != nil {
return nil, err
}
req.Header.Set("Content-Type", "application/json; charset=utf-8")
return req, nil
}
func parseResponseBody(body io.ReadCloser, intf interface{}, d debug) error {
response, err := ioutil.ReadAll(body)
if err != nil {
return err
}
if d.Debug() {
d.Debugln("parseResponseBody", string(response))
}
return json.Unmarshal(response, intf)
}
func postLocalWithMultipartResponse(ctx context.Context, client httpClient, method, fpath, fieldname string, values url.Values, intf interface{}, d debug) error {
fullpath, err := filepath.Abs(fpath)
if err != nil {
return err
}
file, err := os.Open(fullpath)
if err != nil {
return err
}
defer file.Close()
return postWithMultipartResponse(ctx, client, method, filepath.Base(fpath), fieldname, values, file, intf, d)
}
func postWithMultipartResponse(ctx context.Context, client httpClient, path, name, fieldname string, values url.Values, r io.Reader, intf interface{}, d debug) error {
pipeReader, pipeWriter := io.Pipe()
wr := multipart.NewWriter(pipeWriter)
errc := make(chan error)
go func() {
defer pipeWriter.Close()
ioWriter, err := wr.CreateFormFile(fieldname, name)
if err != nil {
errc <- err
return
}
_, err = io.Copy(ioWriter, r)
if err != nil {
errc <- err
return
}
if err = wr.Close(); err != nil {
errc <- err
return
}
}()
req, err := fileUploadReq(ctx, path, values, pipeReader)
if err != nil {
return err
}
req.Header.Add("Content-Type", wr.FormDataContentType())
req = req.WithContext(ctx)
resp, err := client.Do(req)
if err != nil {
return err
}
defer resp.Body.Close()
err = checkStatusCode(resp, d)
if err != nil {
return err
}
select {
case err = <-errc:
return err
default:
return newJSONParser(intf)(resp)
}
}
func doPost(ctx context.Context, client httpClient, req *http.Request, parser responseParser, d debug) error {
req = req.WithContext(ctx)
resp, err := client.Do(req)
if err != nil {
return err
}
defer resp.Body.Close()
err = checkStatusCode(resp, d)
if err != nil {
return err
}
return parser(resp)
}
// post JSON.
func postJSON(ctx context.Context, client httpClient, endpoint, token string, json []byte, intf interface{}, d debug) error {
reqBody := bytes.NewBuffer(json)
req, err := http.NewRequest("POST", endpoint, reqBody)
if err != nil {
return err
}
req.Header.Set("Content-Type", "application/json")
req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", token))
return doPost(ctx, client, req, newJSONParser(intf), d)
}
// post a url encoded form.
func postForm(ctx context.Context, client httpClient, endpoint string, values url.Values, intf interface{}, d debug) error {
reqBody := strings.NewReader(values.Encode())
req, err := http.NewRequest("POST", endpoint, reqBody)
if err != nil {
return err
}
req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
return doPost(ctx, client, req, newJSONParser(intf), d)
}
func getResource(ctx context.Context, client httpClient, endpoint string, values url.Values, intf interface{}, d debug) error {
req, err := http.NewRequest("GET", endpoint, nil)
if err != nil {
return err
}
req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
req.URL.RawQuery = values.Encode()
return doPost(ctx, client, req, newJSONParser(intf), d)
}
func parseAdminResponse(ctx context.Context, client httpClient, method string, teamName string, values url.Values, intf interface{}, d debug) error {
endpoint := fmt.Sprintf(WEBAPIURLFormat, teamName, method, time.Now().Unix())
return postForm(ctx, client, endpoint, values, intf, d)
}
func logResponse(resp *http.Response, d debug) error {
if d.Debug() {
text, err := httputil.DumpResponse(resp, true)
if err != nil {
return err
}
d.Debugln(string(text))
}
return nil
}
func okJSONHandler(rw http.ResponseWriter, r *http.Request) {
rw.Header().Set("Content-Type", "application/json")
response, _ := json.Marshal(SlackResponse{
Ok: true,
})
rw.Write(response)
}
// timerReset safely reset a timer, see time.Timer.Reset for details.
func timerReset(t *time.Timer, d time.Duration) {
if !t.Stop() {
<-t.C
}
t.Reset(d)
}
func checkStatusCode(resp *http.Response, d debug) error {
if resp.StatusCode == http.StatusTooManyRequests {
retry, err := strconv.ParseInt(resp.Header.Get("Retry-After"), 10, 64)
if err != nil {
return err
}
return &RateLimitedError{time.Duration(retry) * time.Second}
}
// Slack seems to send an HTML body along with 5xx error codes. Don't parse it.
if resp.StatusCode != http.StatusOK {
logResponse(resp, d)
return statusCodeError{Code: resp.StatusCode, Status: resp.Status}
}
return nil
}
type responseParser func(*http.Response) error
func newJSONParser(dst interface{}) responseParser {
return func(resp *http.Response) error {
return json.NewDecoder(resp.Body).Decode(dst)
}
}
func newTextParser(dst interface{}) responseParser {
return func(resp *http.Response) error {
b, err := ioutil.ReadAll(resp.Body)
if err != nil {
return err
}
if !bytes.Equal(b, []byte("ok")) {
return errors.New(string(b))
}
return nil
}
}
func newContentTypeParser(dst interface{}) responseParser {
return func(req *http.Response) (err error) {
var (
ctype string
)
if ctype, _, err = mime.ParseMediaType(req.Header.Get("Content-Type")); err != nil {
return err
}
switch ctype {
case "application/json":
return newJSONParser(dst)(req)
default:
return newTextParser(dst)(req)
}
}
}