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GET request with header to open a URL and retrieve header in Angular app

I have an Angular app with a route say /register which can be accessible on http://xyc.com/register
I want to make a GET call to this url and pass a header in that request.
Now, I want my angular app to be able to read header from the request and store it in cookie.
I am not sure where and how to retrieve the header from the request in my Angular app? Should I ideally create an interceptor for this and do request.headers to get the header I want? I tried it like this:
export class SomeInterceptor implements HttpInterceptor {
intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
console.log("headers = " + JSON.stringify(request.headers));
...
...
}
}
Not sure if this is the right approach?
Then, I wanted to test (from browser) if the header is retrieved properly by sending a GET request to the URL and seeing if the header prints using console.log. For this I tried to use a JSP to send a GET request to this URL (along with the header) in order to test if the header is retrieved correctly in my Angular app. But I am not sure how to do it.
In my JSP code, I tried the following:
response.setHeader("myHeader", "test-header");
response.setStatus(HttpServletResponse.SC_MOVED_TEMPORARILY);
response.setHeader("Location", "http://xyc.com/register");
However, I don't see my header printed. Not sure if my approach to read the header is wrong or the way I am testing is wrong. Any help?

Cookie ideally is way for server to send data to browser to keep track of anything that server wants to remember. E.g. Authentication token or anything that can track session of user. What you are trying to do is other way round. I would have ideally set cookie as a part of response from server than actually reading at browser and setting it there. Ideally in most of the cases browser too does not need to explicitly set, as once set it becomes a part of every request that is send.

Put-Request throws 401 [no body] error and cannot be stored in the response entity

I want to change data on a server via a put request, but I always get a 401 [no body] error. The response looks like the following:
I do not really understand why I get this error, because my body is not empty. My code looks like this and the values seem to be okay too. Does anyone have any idea what I'm doing wrong?
Postman Update:
The values are different right now (consent and authorisation) since its basically a new request but the values were correct before too so this change should not make a difference.

Looks like you are simply passing invalid authorization header, or maybe not passing it at all.
What happens is that you make a RestTemplate exchange call, then you get 401 from that request, and Spring propagates it and returns 500 - Internal Server Error, because there is no error handling in place.
EDIT: According to your screenshots, you are not replacing your path variables. Update the way you build your URL as listed below.
Map<String, String> pathVars = new HashMap<>(2);
pathVars.put("consent-id", consentId);
pathVars.put("authorisation-id", authorisationId);
UriComponents uri = UriComponentsBuilder.fromUri(mainLink)
.path("consents/{consent-id}/authorizations/{authorisation-id}")
.buildAndExpand(pathVars);

Verify if your authorization-id is correct
if the token has a type for example Bearer you must write so:
"Authorization": "Bearer rrdedzfdgf........."
and make sure that there is only one space between Bearer and the token

Often the problem comes from the browser locally;
if your site is online, save the part and deploy the last modifications of the site and make the test
otherwise if it is a mobile application test it on a smartphone and not a browser;
in case none of this works, do it with your backend, it works with this

I had a problem where the I would add an extra character to a password. And Insomnia(Or Postman) would return a JSON response from the server along with a 401 HTTP status code. But when I did the same thing inside a springboot app, when using catch(HttpServerErrorException e){System.out.prinln(e.getMessage());} the e.getMessage would have [no body]. I think that is a feature built in the HttpServerErrorException class where it doesn't provide the body for security purposes. Since whoever is requesting is not authorized they should not have access to it.

Open an authenticated image served by django from java using Apache http client

I Am serving an authenticated image using django. The image is behind a view which require login, and in the end I have to check more things than just the authentication.
Because of a reason to complicated to explain here, I cannot use the real url to the image, but I Am serving it with a custom url leading to the authenticated view.
From java the image must be reachable, to save or display. For this part I use Apache httpclient.
In Apacahe I tried a lot of things (every example and combination of examples...) but can't seem to get it working.
For other parts of the webapp I use django-rest-framwork, which I succesfully connected to from java (and c and curl).
I use the login_reuired decorator in django, which makes the attempt to get to the url redirect to a login page first.
Trying the link and the login in a webviewer, I see the 200 code (OK) in the server console.
Trying the link with the httpclient, I get a 302 Found in the console.... (looking up 302, it means a redirect..)
this is what I do in django:
in urls.py:
url(r'^photolink/(?P<filename>.*)$', 'myapp.views.photolink',name='photolink'),
in views.py:
import mimetypes
import os
#login_required
def photolink(request, filename):
# from the filename I get the image object, for this question not interesting
# there is a good reason for this complicated way to reach a photo, but not the point here
filename_photo = some_image_object.url
base_filename=os.path.basename(filename_photo)
# than this is the real path and filename to the photo:
path_filename=os.path.join(settings.MEDIA_ROOT,'photos',mac,base_filename)
mime = mimetypes.guess_type(filename_photot)[0]
logger.debug("mimetype response = %s" % mime)
image_data = open(path_filename, 'rb').read()
return HttpResponse(image_data, mimetype=mime)
by the way, if i get this working i need another decorator to pass some other tests....
but i first need to get this thing working....
for now it's not a secured url.... plain http.
in java i tried a lot of things... using apache's httpclient 4.2.1
proxy, cookies, authentication negociation, with follow redirects... and so on...
Am I overlooking some basic thing here?...
it seems the login of the website client is not suitable for automated login...
so the problem can be in my code in django....or in the java code....

In the end the problem was, using HTTP authorization.
Which is not by default used in the login_required decorator.
adding a custom decorator that checks for HTTP authorization did the trick:
see this example: http://djangosnippets.org/snippets/243/

Options for passing data across HTTP redirects

I am working on a Web application and need to pass data across HTTP redirects. For example:
http://foo.com/form.html
POSTs to
http://foo.com/form/submit.html
If there is an issue with the data, the Response is redirected back to
http://foo.com/form.html?error=Some+error+message
and the query param "error"'s value is displayed on the page.
Is there any other reliable way to pass data across redirects (ie HTTP headers, etc.).
Passing the data as query params works but isn't ideal because:
its cleartext (and in the query string, so SSL cant be relied on to encyrpt) so I wouldn't want to pass sensitive data
URIs are limited in length by the browser (albiet the length is generally fairly long).
IMPORTANT: This platform is state-less and distributed across many app servers, so I can't track the data in a server-side session object.

From the client-server interaction point of view, this is a server internal dispatch issue.
Browsers are not meant to re-post the entity of the initial request automatically according to the HTTP specification: "The action required MAY be carried out by the user agent without interaction with the user if and only if the method used in the second request is GET or HEAD."
If it's not already the case, make form.html dynamic so that it's an HTML static file. Send the POST request to itself and pre-fill the value in case of error. Alternatively, you could make submit.html use the same template as form.html if there is a problem.
its cleartext (and in the query string, so SSL cant be relied on to
encyrpt) so I wouldn't want to pass sensitive data
I'm not sure what the issue is here. You're submitting everything over plain HTTP anyway. Cookie, query parameters and request entity will all be visible. Using HTTPS would actually protect all this, although query parameters can still be an issue with browser history and server logs (that's not part of the connection, which is what TLS protects).

I think using cookies would be a reasonable solution depending on the amount of data. As you can't track it on the server side (by using a sessions for example, which would be much simpler)

You can store error message in database on server and reference to it by id:
http://foo.com/form.html?error_id=42
If error texts are fixed you even don't need to use a database.
Also, you can use Web Storage. Instead of redirection with "Location" header you can display output page with this JavaScript:
var error_message = "Something is wrong";
if( typeof(Storage) !== "undefined" ) {
localStorage.error_message = error_message;
else {
// fallback for IE < 8
alert(error_message);
}
location.href = "new url";
And after redirection you can read localStorage.error_message using JavaScript and display the message.

Why do I get an error 500 when I send POST data to an ASP.NET MVC site through Android?

I'm trying to create an android app to check my tests scores of my engineering school. In order to download the Word containing the scores, I need to login to the portal.
I thought it would be simple to do it by sending a POST request.
After bypassing the problem of the self-signed certificate (or whatever) thanks to the code on this page : Self-signed SSL acceptance on Android
I still get an 500 error while trying to send any POST request to the login page, which is here : https://e-campus.hei.fr/ERP-prod/pc_mv_login.aspx
I tried various codes from the web to send the POST data (especially How to do a HTTP Post in Android? this one). And even on a pure java app, I get a 500.
When I point the URL to another testing page, I manage to get it working, but not on https://e-campus.hei.fr/ERP-prod/pc_mv_login.aspx
Could anyone explain to me why it doesn't work or help me get rid of this error ?
EDIT:
This is what is being sent through my browser (According to chrome developper tools)
__EVENTTARGET:
__EVENTARGUMENT:
__VIEWSTATE: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
Username:******
Password:******
Langues:fr
Button1:Connecter :
This is the string that i send :
String parameters = "__EVENTTARGET=&__EVENTARGUMENT=&__VIEWSTATE="
+ URLEncoder
.encode("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",
"UTF-8") + "&Username="
+ URLEncoder.encode(mUsername, "UTF-8") + "&Password="
+ URLEncoder.encode(mPassword, "UTF-8")
+ "&Langues=fr&Button1="
+ URLEncoder.encode("Connecter :", "UTF-8");

HTTP error 500 just means that the server side code failed. It has a bug, for example a NullPointerException was been thrown over there. If the response body doesn't contain anything sensible (e.g. a stacktrace) so that you could learn how it is caused and so change the request accordingly, then your best bet is to contact the server admin and report about this bug in the server code and ask how to correctly perform a programmatic login.
If that is not an option for some reason, then you should doublecheck if you don't forget to send a specific cookie, header and/or parameter. Probably the server side code was expecting it, but it was null and the code was buggy and hence it totally broke with a 500. I'd suggest to use Firebug to track the entire HTTP traffic and compare it with the headers/parameters you've set. Probably you need to send a specific cookie back? Or you need to send the name=value pair of the submit button? Etcetera.
Update: you're sending the wrong __VIEWSTATE value along. The website runs on ASP.NET MVC which is a component based MVC framework (like as JSF in Java EE). It stores the component tree as "view state". You should not send a random/non-existing/invalidated view state back as paramter, but a valid one. You need to rewrite the HTTP client so that it first fires a GET request on the page with the form and then use a HTML parser (Jsoup?) to extract the value of the hidden __VIEWSTATE input field and finally fire a POST request with exactly that value (and exactly the same cookie in the request header!).
Like as in JSF, the view state is part of CSRF attack prevention. You cannot submit the form without first requesting the form from the website itself in the same session.