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