Use upstream slack-go/slack again (#1018)

vendor/github.com/slack-go/slack/slack.go

@@ -0,0 +1,153 @@
+package slack
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"net/http"
+	"net/url"
+	"os"
+)
+
+const (
+	// APIURL of the slack api.
+	APIURL = "https://slack.com/api/"
+	// WEBAPIURLFormat ...
+	WEBAPIURLFormat = "https://%s.slack.com/api/users.admin.%s?t=%d"
+)
+
+// httpClient defines the minimal interface needed for an http.Client to be implemented.
+type httpClient interface {
+	Do(*http.Request) (*http.Response, error)
+}
+
+// ResponseMetadata holds pagination metadata
+type ResponseMetadata struct {
+	Cursor string `json:"next_cursor"`
+}
+
+func (t *ResponseMetadata) initialize() *ResponseMetadata {
+	if t != nil {
+		return t
+	}
+
+	return &ResponseMetadata{}
+}
+
+// AuthTestResponse ...
+type AuthTestResponse struct {
+	URL    string `json:"url"`
+	Team   string `json:"team"`
+	User   string `json:"user"`
+	TeamID string `json:"team_id"`
+	UserID string `json:"user_id"`
+	// EnterpriseID is only returned when an enterprise id present
+	EnterpriseID string `json:"enterprise_id,omitempty"`
+}
+
+type authTestResponseFull struct {
+	SlackResponse
+	AuthTestResponse
+}
+
+// Client for the slack api.
+type ParamOption func(*url.Values)
+
+type Client struct {
+	token      string
+	endpoint   string
+	debug      bool
+	log        ilogger
+	httpclient httpClient
+}
+
+// Option defines an option for a Client
+type Option func(*Client)
+
+// OptionHTTPClient - provide a custom http client to the slack client.
+func OptionHTTPClient(client httpClient) func(*Client) {
+	return func(c *Client) {
+		c.httpclient = client
+	}
+}
+
+// OptionDebug enable debugging for the client
+func OptionDebug(b bool) func(*Client) {
+	return func(c *Client) {
+		c.debug = b
+	}
+}
+
+// OptionLog set logging for client.
+func OptionLog(l logger) func(*Client) {
+	return func(c *Client) {
+		c.log = internalLog{logger: l}
+	}
+}
+
+// OptionAPIURL set the url for the client. only useful for testing.
+func OptionAPIURL(u string) func(*Client) {
+	return func(c *Client) { c.endpoint = u }
+}
+
+// New builds a slack client from the provided token and options.
+func New(token string, options ...Option) *Client {
+	s := &Client{
+		token:      token,
+		endpoint:   APIURL,
+		httpclient: &http.Client{},
+		log:        log.New(os.Stderr, "slack-go/slack", log.LstdFlags|log.Lshortfile),
+	}
+
+	for _, opt := range options {
+		opt(s)
+	}
+
+	return s
+}
+
+// AuthTest tests if the user is able to do authenticated requests or not
+func (api *Client) AuthTest() (response *AuthTestResponse, error error) {
+	return api.AuthTestContext(context.Background())
+}
+
+// AuthTestContext tests if the user is able to do authenticated requests or not with a custom context
+func (api *Client) AuthTestContext(ctx context.Context) (response *AuthTestResponse, err error) {
+	api.Debugf("Challenging auth...")
+	responseFull := &authTestResponseFull{}
+	err = api.postMethod(ctx, "auth.test", url.Values{"token": {api.token}}, responseFull)
+	if err != nil {
+		return nil, err
+	}
+
+	return &responseFull.AuthTestResponse, responseFull.Err()
+}
+
+// Debugf print a formatted debug line.
+func (api *Client) Debugf(format string, v ...interface{}) {
+	if api.debug {
+		api.log.Output(2, fmt.Sprintf(format, v...))
+	}
+}
+
+// Debugln print a debug line.
+func (api *Client) Debugln(v ...interface{}) {
+	if api.debug {
+		api.log.Output(2, fmt.Sprintln(v...))
+	}
+}
+
+// Debug returns if debug is enabled.
+func (api *Client) Debug() bool {
+	return api.debug
+}
+
+// post to a slack web method.
+func (api *Client) postMethod(ctx context.Context, path string, values url.Values, intf interface{}) error {
+	return postForm(ctx, api.httpclient, api.endpoint+path, values, intf, api)
+}
+
+// get a slack web method.
+func (api *Client) getMethod(ctx context.Context, path string, values url.Values, intf interface{}) error {
+	return getResource(ctx, api.httpclient, api.endpoint+path, values, intf, api)
+}