Sending JSON to Slack in a HTTP POST request

Question

I\'m trying to send a message using Slack\'s chat.postMessage API call. I have no problems encoding my test messages within HTTP GET, but I\'m trying to achieve the same res

Answer 1

not_authed means No authentication token provided.

Which token are you passing along in the request? You need to pass your OAuth token, which you can get from here.

Answer 2

If you are using java and spring such dependency, Voila!! here you go

     * Make a POST call to the chat.PostMessage.
     */
    public void chatPostMessage(Message message)
    {
        RestTemplate restTemplate = new RestTemplate();

        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);

        MultiValueMap<String, String> map = new LinkedMultiValueMap<String, String>();
        map.add("token", slackPostMessageToken); //Required
        map.add("text", message.getText());//Required
        map.add("channel", message.getChannelId());//Required

        map.add("unfurl_links","true");
        map.add("as_user","false");//Default false
        map.add("icon_emoji",":chart_with_upwards_trend:");
        map.add("attachments","[\n" +
                "        {\n" +
                "            \"fallback\": \"Required plain-text summary of the attachment.\",\n" +
                "            \"color\": \"#36a64f\",\n" +
                "            \"pretext\": \"Optional text that appears above the attachment block\",\n" +
                "            \"author_name\": \"Bobby Tables\",\n" +
                "            \"author_link\": \"http://flickr.com/bobby/\",\n" +
                "            \"author_icon\": \"http://flickr.com/icons/bobby.jpg\",\n" +
                "            \"title\": \"Slack API Documentation\",\n" +
                "            \"title_link\": \"https://api.slack.com/\",\n" +
                "            \"text\": \"Optional text that appears within the attachment\",\n" +
                "            \"fields\": [\n" +
                "                {\n" +
                "                    \"title\": \"Priority\",\n" +
                "                    \"value\": \"High\",\n" +
                "                    \"short\": false\n" +
                "                }\n" +
                "            ],\n" +
                "            \"image_url\": \"http://my-website.com/path/to/image.jpg\",\n" +
                "            \"thumb_url\": \"http://example.com/path/to/thumb.png\",\n" +
                "            \"footer\": \"Datoo ©\",\n" +
                "            \"ts\": "+System.currentTimeMillis()+"" +
                "        }\n" +
                "    ]");
        map.add("username","III");


        HttpEntity<MultiValueMap<String, String>> request = new HttpEntity<MultiValueMap<String, String>>(map, headers);

        try {
            ResponseEntity<String> response = restTemplate.postForEntity(slackPostMessageUrl, request, String.class);
            System.out.println(response);
        }
        catch (RestClientException e) {
            logger.error("Error :-( : ", e);
        }
    }

Answer 3

This may not qualify for the complete answer, but if the purpose is to send a message attachment, you can send a urlencoded JSON structure as the value of the attachments parameter, like so (split into multiple lines for clarity):

https://slack.com/api/chat.postMessage?
token=YOUR-TOKE-N000&
channel=%23alerts&
text=Hi&
attachments=%5B%7B%22color%22%3A%22good%22%2C%22fallback%22%3A%22plain+text%22%2C%22text%22%3A%22colored+text%22%7D%5D

The value of attachments is URL-encoded [{"color":"good","fallback":"plain text","text":"colored text"}]. You should be able to use all attachment attributes described here.

Answer 4

Slack has been updated, this now works. Try this example:

curl -X POST -H 'Content-type: application/json' --data '{"text":"This is a line of text.\nAnd this is another one."}' https://hooks.slack.com/services/AAAAAA/BBBBBB/CCCCCC

See https://api.slack.com/incoming-webhooks for documentation.

Answer 5

On postman you can frame your request like this:

url(POST) : https://slack.com/api/chat.postMessage

Then under Headers section put these two headers:

1. key(Content-Type) value(application/json)

2. key(Authorization) value(YOUR-TOKEN-NAME)

Then in Body section in raw form put your data:

    {"channel": "CHANNEL-NAME", "data": "You better post this to channel"}