In the Cumulocity guide, https://www.cumulocity.com/guides/event-language/introduction/, there is a mention of Event Streams for HTTP.
HTTP ResponseReceived SendReqeust This group of events represents sending http requests to external services.
This means we can send outbound HTTP request to external services using the "SendRequest" stream. However, I did not find any further details in any documentation. Can you please provide the template CEL details for SendRequest, and how to configure the same in Cumulocity?
I can not help you using the actual engine (Apama) but I can give you one example using Esper.
#Name("Sending the http request")
#Resilient
insert into
SendRequest
select
'post' as method,
'https://tenant.cumulocity.com/inventory/managedObjects' as url,
'Basic .....' as authorization,
'application/json' as contentType,
toJSON(m) as body
from anyEventStream m;
The toJSON if a function that takes the event stream and return is equivalent in json.
You can find more info here. This info is hide from the actual docs and think it is because they want to push developers to use APAMA instead ESPER.
Hope this helps.
Related
Background:
Looking at some links like these below, I noticed two unique sets of descriptions for GET versus POST.
One description states that the difference is in how the information is sent: GET sends that information through the URL whereas POST sends that information through the HTTP request body.
Another description states that the difference is in which way that
information is sent: GET sends information to the server whereas POST
requests information from the server.
I find these descriptions to be lacking for the following reasons:
What if I want to get something from the server (GET) but I am sending a large amount of data first (eg. 50MB of text) so I would need to send it in the HTTP request body (POST). Would it be OK to use POST to get something from the server?
What if I don't want sensitive information to be stored in the URL, is it OK to instead use POST everytime?
The jquery GET function has the same method signature as the jquery POST function (see documentation), specifically it can also send data as A plain object or string that is sent to the server with the request, which I interpret as being added to the HTTP request body. If data for GET can be sent via the HTTP request body, then to me, this contradicts most of these sites that claim that as one of the differentiating descriptions of POST vs GET.
Nothing's to stop me from creating API endpoints which are GET but behave like POST (or PUT, or DELETE or PATCH)
Question:
Is the lack of strict descriptions because of my poor understanding, because of the ad hoc development process for HTTP/Ajax or is it something else entirely?
Supporting Links:
HTTP Request Methods
GET vs. POST
GET vs POST: Key Difference between HTTP Methods
jQuery - AJAX get() and post() Methods
Thank you for the nice work you put into this amazing library.
I have an issue with my request adapter but only with the MultipartFormData.
I want to be able to update the body of the request but when the request gets in the adapter, I'm getting a nil httpBody. I only get this behaviour on Multipart, not on classic POST requests.
I'm trying to sign the request with an oauth2 token (async), but the particularity of this API is that the token is sent in the body and not in the headers.
There's a body as the metrics in the response say (Request Body Transfer Bytes) 231306
I'm using Alamofire 5.0.0
This is most likely due to multipart forms using UploadRequests (and therefore URLSessionUploadTasks) which do not include the body data as part of the URLRequest for performance reasons. If you update your question with what you're trying to do to the body, perhaps I can provide an alternate solution. If nothing else, you could manually create multipart uploads by using MultipartFormData.encode() directly and adding the Data to a URLRequest, but that's not recommended for large uploads.
I'm writing a simple api for training using express. Here's my testing code:
var express = require('express');
var app = express();
app.post("/api/:var_name", function(req, res) {
res.send(req.params.var_name);
});
is simply testing to see if POST is working. When I call http://localhost:3000/api/1 I get Cannot GET /api/1, so the server is obviously interpreting the POST request as GET, what do I need to do to call POST instead?
Anything you call in the address bar of your browser will be sent via get. This is due to the fact that post-messages (and almost all other methods) do have a body-part. But there is no way for your browser to send additional information inside the body of the http packet.
If you want to test your routes for any method other than GET I would suggest you download a tool like postman.
https://www.getpostman.com/
BEWARE: This is my preference. You can of curse also use text based browsers like curl to test it.
The server interprets the request according to the verb you set in the HTTP request. If no method/verb is specified it is interpreted as GET(not sure about this part).
When you call that URL, you need to use the method as well. For example if you use the fetch API, you can call it like:
fetch(url, {method:"POST"})
If you're entering it in your browser and expect it to be interpreted as a post request, it's not. All browser url requests are GET. Use a tool like Postman to call different HTTP verbs. It's really useful when creating such APIs.
You can check out this answer on details of how to add body and headers to a post request: Fetch: POST json data
I have a REST server which returns a Link HTTP header with a response to a PUT to indicate the URL of the newly-created entity:
Link:<entities/6>; rel="created"
Is there any possibility to read that link header with Restangular?
The only facility to intercept HTTP requests with Restangular I've met so far is to register a response interceptor in the app config:
restangular.addResponseInterceptor(function (data, operation, what, url, response, deferred) {
console.log(response.headers())
return response.data;
});
However, with above demo implementation in place, the only HTTP header which gets logged is content-type. Still, I can see in the browser development toolbar that a response comes indeed with many additional HTTP response headers, such as Server, Date, and the aforementioned Link.
Why do I not have access to the full array of HTTP response headers through addResponseInterceptor()? Is there any way to capture the HTTP response header in question using Restangular?
Note: I don't search for an answer using HAL or any other special response body format. I would rather like to know whether I can use plain HTTP headers with Restangular or not (if not, I will probably resort to HAL or something).
You don't need a ResponseInterceptor to do this. You just need to set fullResponse to true to get the whole response (including the http headers) every time you do any request.
Restangular.setFullResponse(true);
You can set it globally in your app configuration. Something like this:
angular.module('YourApp')
.config(['RestangularProvider',
function (RestangularProvider) {
RestangularProvider.setFullResponse(true);
...
Then, every time you receive a response, you can access all the response headers.
Restangular.all('users').getList().then(function(response) {
$scope.users = response.data;
console.log(response.headers);
}
Example:
response.headers('Link')
NOTE: Be careful because using fullResponse, the response data is located in response.data, not directly in response.
EDIT: As #STEVER points, you also need to expose the headers in your server API.
Example:
Access-Control-Expose-Headers: Link
You can get more detailed information in Restangular documentation
Hope it helps.
I need to POST data to a server in a different domain. That server is using SSL and expects the data to be in the form of a JSON string. I am attempting to do this from javascript.
I create the data and use JSON.stringify() to get it into the correct format. Then I send it as follows:
var url = "https://api.postageapp.com/v.1.0/send_message.json";
http=new XMLHttpRequest();
http.open("POST", url, true);
http.setRequestHeader("Content-type", "application/json");
http.setRequestHeader("Connection", "close");
// create the data in a data structure named post_data
var JSONText = JSON.stringify(post_data);
http.send(JSONText);
Doing a packet trace I see my client do a handshake with the server but then twice the server replies with "Encrypted alert" including the last time it sends a packet back. The browser debugger always shows a 405 - Method Now Allowed error.
What am I missing to get this to work? When they try it within their domain it runs fine.
You need server to return a HTTP Header like that:
header('Access-Control-Allow-Origin: *');
Live example:
Making cross domain JavaScript requests using XMLHttpRequest or XDomainRequest
You cannot do a cross domain post like that.
Alternative is to use Server side proxy (read this link for a nice explanation as to why you can't do that) or iframe approach.
Strictly speaking it should not be possible (due to security issues) however using a workaround called JSONP you can achieve this with a RESTful web service.
See the link below.
http://en.wikipedia.org/wiki/JSONP
MS has some code you can download somewhere on the internet with specific bindings the code is called.
JSONPBehaviour.cs
JSONPBindingElement.cs
JSONPBindingExtension.cs
JSONPEncoderFactory.cs