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// Copyright (c) 2015 Mattermost, Inc. All Rights Reserved.
// See License.txt for license information.
package model
import (
"bytes"
"encoding/json"
"fmt"
"io"
"regexp"
"strings"
)
const (
DEFAULT_WEBHOOK_USERNAME = "webhook"
)
type IncomingWebhook struct {
Id string `json:"id"`
CreateAt int64 `json:"create_at"`
UpdateAt int64 `json:"update_at"`
DeleteAt int64 `json:"delete_at"`
UserId string `json:"user_id"`
ChannelId string `json:"channel_id"`
TeamId string `json:"team_id"`
DisplayName string `json:"display_name"`
Description string `json:"description"`
}
type IncomingWebhookRequest struct {
Text string `json:"text"`
Username string `json:"username"`
IconURL string `json:"icon_url"`
ChannelName string `json:"channel"`
Props StringInterface `json:"props"`
Attachments []*SlackAttachment `json:"attachments"`
Type string `json:"type"`
}
func (o *IncomingWebhook) ToJson() string {
b, err := json.Marshal(o)
if err != nil {
return ""
} else {
return string(b)
}
}
func IncomingWebhookFromJson(data io.Reader) *IncomingWebhook {
decoder := json.NewDecoder(data)
var o IncomingWebhook
err := decoder.Decode(&o)
if err == nil {
return &o
} else {
return nil
}
}
func IncomingWebhookListToJson(l []*IncomingWebhook) string {
b, err := json.Marshal(l)
if err != nil {
return ""
} else {
return string(b)
}
}
func IncomingWebhookListFromJson(data io.Reader) []*IncomingWebhook {
decoder := json.NewDecoder(data)
var o []*IncomingWebhook
err := decoder.Decode(&o)
if err == nil {
return o
} else {
return nil
}
}
func (o *IncomingWebhook) IsValid() *AppError {
if len(o.Id) != 26 {
return NewLocAppError("IncomingWebhook.IsValid", "model.incoming_hook.id.app_error", nil, "")
}
if o.CreateAt == 0 {
return NewLocAppError("IncomingWebhook.IsValid", "model.incoming_hook.create_at.app_error", nil, "id="+o.Id)
}
if o.UpdateAt == 0 {
return NewLocAppError("IncomingWebhook.IsValid", "model.incoming_hook.update_at.app_error", nil, "id="+o.Id)
}
if len(o.UserId) != 26 {
return NewLocAppError("IncomingWebhook.IsValid", "model.incoming_hook.user_id.app_error", nil, "")
}
if len(o.ChannelId) != 26 {
return NewLocAppError("IncomingWebhook.IsValid", "model.incoming_hook.channel_id.app_error", nil, "")
}
if len(o.TeamId) != 26 {
return NewLocAppError("IncomingWebhook.IsValid", "model.incoming_hook.team_id.app_error", nil, "")
}
if len(o.DisplayName) > 64 {
return NewLocAppError("IncomingWebhook.IsValid", "model.incoming_hook.display_name.app_error", nil, "")
}
if len(o.Description) > 128 {
return NewLocAppError("IncomingWebhook.IsValid", "model.incoming_hook.description.app_error", nil, "")
}
return nil
}
func (o *IncomingWebhook) PreSave() {
if o.Id == "" {
o.Id = NewId()
}
o.CreateAt = GetMillis()
o.UpdateAt = o.CreateAt
}
func (o *IncomingWebhook) PreUpdate() {
o.UpdateAt = GetMillis()
}
// escapeControlCharsFromPayload escapes control chars (\n, \t) from a byte slice.
// Context:
// JSON strings are not supposed to contain control characters such as \n, \t,
// ... but some incoming webhooks might still send invalid JSON and we want to
// try to handle that. An example invalid JSON string from an incoming webhook
// might look like this (strings for both "text" and "fallback" attributes are
// invalid JSON strings because they contain unescaped newlines and tabs):
// `{
// "text": "this is a test
// that contains a newline and tabs",
// "attachments": [
// {
// "fallback": "Required plain-text summary of the attachment
// that contains a newline and tabs",
// "color": "#36a64f",
// ...
// "text": "Optional text that appears within the attachment
// that contains a newline and tabs",
// ...
// "thumb_url": "http://example.com/path/to/thumb.png"
// }
// ]
// }`
// This function will search for `"key": "value"` pairs, and escape \n, \t
// from the value.
func escapeControlCharsFromPayload(by []byte) []byte {
// we'll search for `"text": "..."` or `"fallback": "..."`, ...
keys := "text|fallback|pretext|author_name|title|value"
// the regexp reads like this:
// (?s): this flag let . match \n (default is false)
// "(keys)": we search for the keys defined above
// \s*:\s*: followed by 0..n spaces/tabs, a colon then 0..n spaces/tabs
// ": a double-quote
// (\\"|[^"])*: any number of times the `\"` string or any char but a double-quote
// ": a double-quote
r := `(?s)"(` + keys + `)"\s*:\s*"(\\"|[^"])*"`
re := regexp.MustCompile(r)
// the function that will escape \n and \t on the regexp matches
repl := func(b []byte) []byte {
if bytes.Contains(b, []byte("\n")) {
b = bytes.Replace(b, []byte("\n"), []byte("\\n"), -1)
}
if bytes.Contains(b, []byte("\t")) {
b = bytes.Replace(b, []byte("\t"), []byte("\\t"), -1)
}
return b
}
return re.ReplaceAllFunc(by, repl)
}
func decodeIncomingWebhookRequest(by []byte) (*IncomingWebhookRequest, error) {
decoder := json.NewDecoder(bytes.NewReader(by))
var o IncomingWebhookRequest
err := decoder.Decode(&o)
if err == nil {
return &o, nil
} else {
return nil, err
}
}
// To mention @channel via a webhook in Slack, the message should contain
// <!channel>, as explained at the bottom of this article:
// https://get.slack.help/hc/en-us/articles/202009646-Making-announcements
func expandAnnouncement(text string) string {
c1 := "<!channel>"
c2 := "@channel"
if strings.Contains(text, c1) {
return strings.Replace(text, c1, c2, -1)
}
return text
}
// Expand announcements in incoming webhooks from Slack. Those announcements
// can be found in the text attribute, or in the pretext, text, title and value
// attributes of the attachment structure. The Slack attachment structure is
// documented here: https://api.slack.com/docs/attachments
func expandAnnouncements(i *IncomingWebhookRequest) {
i.Text = expandAnnouncement(i.Text)
for _, attachment := range i.Attachments {
attachment.Pretext = expandAnnouncement(attachment.Pretext)
attachment.Text = expandAnnouncement(attachment.Text)
attachment.Title = expandAnnouncement(attachment.Title)
for _, field := range attachment.Fields {
if field.Value != nil {
// Ensure the value is set to a string if it is set
field.Value = expandAnnouncement(fmt.Sprintf("%v", field.Value))
}
}
}
}
func IncomingWebhookRequestFromJson(data io.Reader) *IncomingWebhookRequest {
buf := new(bytes.Buffer)
buf.ReadFrom(data)
by := buf.Bytes()
// Try to decode the JSON data. Only if it fails, try to escape control
// characters from the strings contained in the JSON data.
o, err := decodeIncomingWebhookRequest(by)
if err != nil {
o, err = decodeIncomingWebhookRequest(escapeControlCharsFromPayload(by))
if err != nil {
return nil
}
}
expandAnnouncements(o)
return o
}
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