I'm using Restangular. I would like to get full response so I set
Restangular.setFullResponse(true);
but then I discovered that my custom headers does not work. Documentation for setFullResponse() method says:
in order for Restangular to access custom HTTP headers, your server must respond having the Access-Control-Expose-Headers: set.
I would like to send my custom headers but I don't want to change server settings. Is it possible?
If I leave default settings i.e.setFullResponse(false) there is no issue with custom headers. Is there another solution except changing server settings?
The sentence you cite from the setFullResponse() docs is about what headers from the response your Restangular app will be able to access. And what that is saying is, it’s not possible to access most of the headers from the response unless the server’s already configured to send the right response-header names in the Access-Control-Expose-Headers header.
Without the server setting any value for that header, the only response headers that browsers will let you access from client-side JavaScript in your web app are the Cache-Control,
Content-Language,
Content-Type,
Expires,
Last-Modified
&
Pragma response headers.
See https://fetch.spec.whatwg.org/#cors-safelisted-response-header-name for the spec on that.
I would like to send my custom headers but I don't want to change server settings. Is it possible?
If you mean you want to send custom headers in a request from your client-side Restangular code to the server, please provide more details about exactly which custom headers you want to send.
There too though, there’s another CORS header your server must send in the response: the Access-Control-Allow-Headers response header. If the server isn’t configured to send that with the right header names listed, then your request will fail. The reason in that case is, you will hit https://developer.mozilla.org/en-US/docs/Web/HTTP/Access_control_CORS#Preflighted_requests.
In my Meteor (1.2) application, I make a client-side HTTP.get call over https to a remote server supporting CORS.
var getUrl= "https://remoteserver/;
HTTP.call('GET', getUrl , {}, function (error, response) {
console.log (response);
}
Now, the issue is that set-cookie string is present in HTTP headers of the response of such HTTP call in Chrome's DevTools' Network tab.
However when I call console.log (response) , they're not included. Actually only these 3 properties are printed in response['headers']:
Content-Type
cache-control
last-modified
Digging more in, I found out on Meteor Docs that
Cookies are deliberately excluded from the headers as they are a security risk for this transport. For details and alternatives, see the SockJS documentation.
Now, on the linked SockJS docs, it says that
Basically - cookies are not suited for SockJS model. If you want to authorise a session - provide a unique token on a page, send it as a first thing over SockJS connection and validate it on the server side. In essence, this is how cookies work.
I found this this answer about sockJS but it looks outdated an not specific to Meteor.
The remote server expects me to use cookie-set header, so I have no choice. Also, for established scalability reasons, the HTTP.call must be done client-side (server-side was not an issue at all)
What solution / workaround can I adopt?
This package looks to be designed to help in situations like this, though I have not used it:
https://atmospherejs.com/dandv/http-more
I am building a web API. I found whenever I use Chrome to POST, GET to my API, there is always an OPTIONS request sent before the real request, which is quite annoying. Currently, I get the server to ignore any OPTIONS requests. Now my question is what's good to send an OPTIONS request to double the server's load? Is there any way to completely stop the browser from sending OPTIONS requests?
edit 2018-09-13: added some precisions about this pre-flight request and how to avoid it at the end of this reponse.
OPTIONS requests are what we call pre-flight requests in Cross-origin resource sharing (CORS).
They are necessary when you're making requests across different origins in specific situations.
This pre-flight request is made by some browsers as a safety measure to ensure that the request being done is trusted by the server.
Meaning the server understands that the method, origin and headers being sent on the request are safe to act upon.
Your server should not ignore but handle these requests whenever you're attempting to do cross origin requests.
A good resource can be found here http://enable-cors.org/
A way to handle these to get comfortable is to ensure that for any path with OPTIONS method the server sends a response with this header
Access-Control-Allow-Origin: *
This will tell the browser that the server is willing to answer requests from any origin.
For more information on how to add CORS support to your server see the following flowchart
http://www.html5rocks.com/static/images/cors_server_flowchart.png
edit 2018-09-13
CORS OPTIONS request is triggered only in somes cases, as explained in MDN docs:
Some requests don’t trigger a CORS preflight. Those are called “simple requests” in this article, though the Fetch spec (which defines CORS) doesn’t use that term. A request that doesn’t trigger a CORS preflight—a so-called “simple request”—is one that meets all the following conditions:
The only allowed methods are:
GET
HEAD
POST
Apart from the headers set automatically by the user agent (for example, Connection, User-Agent, or any of the other headers with names defined in the Fetch spec as a “forbidden header name”), the only headers which are allowed to be manually set are those which the Fetch spec defines as being a “CORS-safelisted request-header”, which are:
Accept
Accept-Language
Content-Language
Content-Type (but note the additional requirements below)
DPR
Downlink
Save-Data
Viewport-Width
Width
The only allowed values for the Content-Type header are:
application/x-www-form-urlencoded
multipart/form-data
text/plain
No event listeners are registered on any XMLHttpRequestUpload object used in the request; these are accessed using the XMLHttpRequest.upload property.
No ReadableStream object is used in the request.
Have gone through this issue, below is my conclusion to this issue and my solution.
According to the CORS strategy (highly recommend you read about it) You can't just force the browser to stop sending OPTIONS request if it thinks it needs to.
There are two ways you can work around it:
Make sure your request is a "simple request"
Set Access-Control-Max-Age for the OPTIONS request
Simple request
A simple cross-site request is one that meets all the following conditions:
The only allowed methods are:
GET
HEAD
POST
Apart from the headers set automatically by the user agent (e.g. Connection, User-Agent, etc.), the only headers which are allowed to be manually set are:
Accept
Accept-Language
Content-Language
Content-Type
The only allowed values for the Content-Type header are:
application/x-www-form-urlencoded
multipart/form-data
text/plain
A simple request will not cause a pre-flight OPTIONS request.
Set a cache for the OPTIONS check
You can set a Access-Control-Max-Age for the OPTIONS request, so that it will not check the permission again until it is expired.
Access-Control-Max-Age gives the value in seconds for how long the response to the preflight request can be cached for without sending another preflight request.
Limitation Noted
For Chrome, the maximum seconds for Access-Control-Max-Age is 600 which is 10 minutes, according to chrome source code
Access-Control-Max-Age only works for one resource every time, for example, GET requests with same URL path but different queries will be treated as different resources. So the request to the second resource will still trigger a preflight request.
Please refer this answer on the actual need for pre-flighted OPTIONS request: CORS - What is the motivation behind introducing preflight requests?
To disable the OPTIONS request, below conditions must be satisfied for ajax request:
Request does not set custom HTTP headers like 'application/xml' or 'application/json' etc
The request method has to be one of GET, HEAD or POST. If POST, content type should be one of application/x-www-form-urlencoded, multipart/form-data, or text/plain
Reference:
https://developer.mozilla.org/en-US/docs/Web/HTTP/Access_control_CORS
When you have the debug console open and the Disable Cache option turned on, preflight requests will always be sent (i.e. before each and every request). if you don't disable the cache, a pre-flight request will be sent only once (per server)
Yes it's possible to avoid options request. Options request is a preflight request when you send (post) any data to another domain. It's a browser security issue. But we can use another technology: iframe transport layer. I strongly recommend you forget about any CORS configuration and use readymade solution and it will work anywhere.
Take a look here:
https://github.com/jpillora/xdomain
And working example:
http://jpillora.com/xdomain/
For a developer who understands the reason it exists but needs to access an API that doesn't handle OPTIONS calls without auth, I need a temporary answer so I can develop locally until the API owner adds proper SPA CORS support or I get a proxy API up and running.
I found you can disable CORS in Safari and Chrome on a Mac.
Disable same origin policy in Chrome
Chrome: Quit Chrome, open an terminal and paste this command: open /Applications/Google\ Chrome.app --args --disable-web-security --user-data-dir
Safari: Disabling same-origin policy in Safari
If you want to disable the same-origin policy on Safari (I have 9.1.1), then you only need to enable the developer menu, and select "Disable Cross-Origin Restrictions" from the develop menu.
As mentioned in previous posts already, OPTIONS requests are there for a reason. If you have an issue with large response times from your server (e.g. overseas connection) you can also have your browser cache the preflight requests.
Have your server reply with the Access-Control-Max-Age header and for requests that go to the same endpoint the preflight request will have been cached and not occur anymore.
I have solved this problem like.
if($_SERVER['REQUEST_METHOD'] == 'OPTIONS' && ENV == 'devel') {
header('Access-Control-Allow-Origin: *');
header('Access-Control-Allow-Headers: X-Requested-With');
header("HTTP/1.1 200 OK");
die();
}
It is only for development. With this I am waiting 9ms and 500ms and not 8s and 500ms. I can do that because production JS app will be on the same machine as production so there will be no OPTIONS but development is my local.
You can't but you could avoid CORS using JSONP.
you can also use a API Manager (like Open Sources Gravitee.io) to prevent CORS issues between frontend app and backend services by manipulating headers in preflight.
Header used in response to a preflight request to indicate which HTTP headers can be used when making the actual request :
content-type
access-control-allow-header
authorization
x-requested-with
and specify the "allow-origin" = localhost:4200 for example
After spending a whole day and a half trying to work through a similar problem I found it had to do with IIS.
My Web API project was set up as follows:
// WebApiConfig.cs
public static void Register(HttpConfiguration config)
{
var cors = new EnableCorsAttribute("*", "*", "*");
config.EnableCors(cors);
//...
}
I did not have CORS specific config options in the web.config > system.webServer node like I have seen in so many posts
No CORS specific code in the global.asax or in the controller as a decorator
The problem was the app pool settings.
The managed pipeline mode was set to classic (changed it to integrated) and the Identity was set to Network Service (changed it to ApplicationPoolIdentity)
Changing those settings (and refreshing the app pool) fixed it for me.
OPTIONS request is a feature of web browsers, so it's not easy to disable it. But I found a way to redirect it away with proxy. It's useful in case that the service endpoint just cannot handle CORS/OPTIONS yet, maybe still under development, or mal-configured.
Steps:
Setup a reverse proxy for such requests with tools of choice (nginx, YARP, ...)
Create an endpoint just to handle the OPTIONS request. It might be easier to create a normal empty endpoint, and make sure it handles CORS well.
Configure two sets of rules for the proxy. One is to route all OPTIONS requests to the dummy endpoint above. Another to route all other requests to actual endpoint in question.
Update the web site to use proxy instead.
Basically this approach is to cheat browser that OPTIONS request works. Considering CORS is not to enhance security, but to relax the same-origin policy, I hope this trick could work for a while. :)
One solution I have used in the past - lets say your site is on mydomain.com, and you need to make an ajax request to foreigndomain.com
Configure an IIS rewrite from your domain to the foreign domain - e.g.
<rewrite>
<rules>
<rule name="ForeignRewrite" stopProcessing="true">
<match url="^api/v1/(.*)$" />
<action type="Rewrite" url="https://foreigndomain.com/{R:1}" />
</rule>
</rules>
</rewrite>
on your mydomain.com site - you can then make a same origin request, and there's no need for any options request :)
It can be solved in case of use of a proxy that intercept the request and write the appropriate headers.
In the particular case of Varnish these would be the rules:
if (req.http.host == "CUSTOM_URL" ) {
set resp.http.Access-Control-Allow-Origin = "*";
if (req.method == "OPTIONS") {
set resp.http.Access-Control-Max-Age = "1728000";
set resp.http.Access-Control-Allow-Methods = "GET, POST, PUT, DELETE, PATCH, OPTIONS";
set resp.http.Access-Control-Allow-Headers = "Authorization,Content-Type,Accept,Origin,User-Agent,DNT,Cache-Control,X-Mx-ReqToken,Keep-Alive,X-Requested-With,If-Modified-Since";
set resp.http.Content-Length = "0";
set resp.http.Content-Type = "text/plain charset=UTF-8";
set resp.status = 204;
}
}
What worked for me was to import "github.com/gorilla/handlers" and then use it this way:
router := mux.NewRouter()
router.HandleFunc("/config", getConfig).Methods("GET")
router.HandleFunc("/config/emcServer", createEmcServers).Methods("POST")
headersOk := handlers.AllowedHeaders([]string{"X-Requested-With", "Content-Type"})
originsOk := handlers.AllowedOrigins([]string{"*"})
methodsOk := handlers.AllowedMethods([]string{"GET", "HEAD", "POST", "PUT", "OPTIONS"})
log.Fatal(http.ListenAndServe(":" + webServicePort, handlers.CORS(originsOk, headersOk, methodsOk)(router)))
As soon as I executed an Ajax POST request and attaching JSON data to it, Chrome would always add the Content-Type header which was not in my previous AllowedHeaders config.
I have seen previous posts about Jetty BadMessage: 400 No Host for HttpChannelOverHttp and I can confirm that I am able to repeat the problem.
I have a Jetty route in Camel Blueprint, which creates another request and forwards on to a Dropwizard service via Camel HTTP.
.process(new Processor() {
//Creates Object for request
}
.marshal(jsonFormat)
.convertBodyTo(String.class)
.setHeader(Exchange.HTTP_URI, simple(serviceEndpoint))
.setHeader(Exchange.HTTP_METHOD, constant(HttpMethod.POST))
.to(userviceEndpoint)
When this request executes, I see the following error on Dropwizard
WARN [2014-11-12 23:15:35,333] org.eclipse.jetty.http.HttpParser: BadMessage: 400 No Host for HttpChannelOverHttp#3aa99dd2{r=0,a=IDLE,uri=-}
This happens constantly, and this problem does not occur when I send a request to the DW service using SOAP-UI (using the serviceEndpoint URL).
Please if anyone has solved this problem, I would like to know how. Thank you.
Capture your network traffic, and post the HTTP request headers you are sending to Jetty.
Odds are that your HTTP client is not sending the Host: header (which is required on HTTP/1.1)
In my case, I was setting header with null value. After removing header having null value from request solved the issue.
Jetty Version: 9.3.8
I got this error when I was making a request with incorrectly formatted headers. So instead of having the header as "X_S_ID: ABC" I had "X_S_ID: ["X_S_ID":BLAH]". So the error sometimes may not literally mean you need to pass a Host header.
Fixing the headers fixed this. Print the exact request you are making and make sure all headers are correctly formatted.
This is a question relating to Apigee configuration.
I want to be able to send the request "Host" header back to our endpoint.
For example :
Request : int.api.com/path/UUID?apiKey=key
or
Request : test.api.com/path/UUID?apiKey=key
I should see in the request X-Host=int.api.com.
I have created a policy that sends back a header X-Host but currently its fixed.
I don't know how to get it to dynamically set he Host header based on the request Host header.
I have tried many things.
Any help appreciated !
Try using an AssignMsg to save the request host header (request.header.x-host) as a another variable (let's call it user3645204.variable). Then you can access user3645204.variable in your response flow.
I have a policy setup to send back this info as a either the response body or as key/values in the response header
<ReleaseInfo>
<RequestTimestamp>%system.time#</RequestTimestamp>
<Host>%system.interface.eth0#</Host>
<VirtualHost>%virtualhost.name#</VirtualHost>
<ApigeeEnvironmentName>%apiproxy.name# - %proxy.name#</ApigeeEnvironmentName>
<ApigeeApplication>%environment.name#</ApigeeApplication>
<DeployedApplicationName>ProxyAPIName</DeployedApplicationName>
<ServiceVersion>1.2.1</ServiceVersion>
</ReleaseInfo>
The system.interface.eth0 and virtualhost.name fit my requirements better