package slack
import (
"bytes"
"context"
"encoding/json"
"errors"
"fmt"
"io"
"io/ioutil"
"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"`
}
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 {
// TODO: this is a bad error string, should clean it up with a breaking changes
// merger.
return fmt.Sprintf("Slack server error: %s.", t.Status)
}
func (t statusCodeError) HTTPStatusCode() int {
return t.Code
}
type RateLimitedError struct {
RetryAfter time.Duration
}
func (e *RateLimitedError) Error() string {
return fmt.Sprintf("Slack rate limit exceeded, retry after %s", e.RetryAfter)
}
func fileUploadReq(ctx context.Context, path string, values url.Values, r io.Reader) (*http.Request, error) {
req, err := http.NewRequest("POST", path, r)
req = req.WithContext(ctx)
if err != nil {
return nil, err
}
req.URL.RawQuery = (values).Encode()
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, path, 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, path, 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, APIURL+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()
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}
}
select {
case err = <-errc:
return err
default:
return parseResponseBody(resp.Body, intf, d)
}
}
func doPost(ctx context.Context, client httpClient, req *http.Request, intf interface{}, d debug) error {
req = req.WithContext(ctx)
resp, err := client.Do(req)
if err != nil {
return err
}
defer resp.Body.Close()
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 parseResponseBody(resp.Body, intf, d)
}
// 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, 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, intf, d)
}
// post to a slack web method.
func postSlackMethod(ctx context.Context, client httpClient, path string, values url.Values, intf interface{}, d debug) error {
return postForm(ctx, client, APIURL+path, values, intf, d)
}
// get a slack web method.
func getSlackMethod(ctx context.Context, client httpClient, path string, values url.Values, intf interface{}, d debug) error {
return getResource(ctx, client, APIURL+path, values, 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, 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)
}
type errorString string
func (t errorString) Error() string {
return string(t)
}
// 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)
}