Develop Reference

Plaid Quickstart Issues (Java)

I am trying to implement Plaid using the sample code provided on the Java Quickstart [sandbox] and am getting issues when I show the Plaid Dialog (javascript). I am able to successfully get a link_token, but I'm never able to show the dialog. It spins for a brief second, then shows me:
oauth uri does not contain a valid oauth_state_id query parameter. Request ID: DBoT92FCo8AORay
I have tried this with an empty redirectUri, as well as "http://localhost:8080/plaid_test.html", which is registered in my developer account.
I am a bit stuck and hoping someone can direct me in the right direction. I've tested with both versions 9.10.0 and the latest (11.9.0).
Curiously, I am able to get the Java Quickstart working directly, but ONLY if I leave the .env PLAID_REDIRECT_URI blank. If I put localhost in there, it fails when trying to get the link token.
Does anyone have any suggestions on how to overcome this setup issue?
Thank you!

I got this error (oauth uri does not contain a valid oauth_state_id query parameter) while creating a new test application in Plaid's Sandbox environment.
Important note: My application does not use OAuth.
The problem turned out to be, in my configuration parameters being passed to usePlaidLink, I was including a receivedRedirectUri key-value pair. Removing that key-value pair entirely resolved the issue for me.
In other words, my React component looked something like:
import { usePlaidLink } from 'react-plaid-link';
function PlaidLink(props) {
const onSuccess = React.useCallback((public_token, metadata) => {
// ...
});
const config = {
token: props.linkToken,
receivedRedirectUri: window.location.href,
onSuccess,
};
const { open, ready } = usePlaidLink(config);
// ...
}
Removing the line with the receivedRedirectUri was the solution for me, getting me past the oauth uri does not contain a valid oauth_state_id query parameter error, and getting the Plaid Link UI to appear in my app successfully.
This Plaid article, which has a number of mentions of "OAuth state ID" (as mentioned in the error message), helped point me toward this solution.

The issue may be the location you are trying to use -- unless you have manually modified the ports or other code used by the Quickstart, you should use http://localhost:3000/ as the PLAID_REDIRECT_URI (make sure to add this to your Dashboard as an allowed redirect URI). When I tried this just now on the Java quickstart (non-Docker version) it worked fine.

How to write a Java code to read fields from a website that requires login and uses POST request?

Need some help with fetching some data from a website.
Previously , we had following code in our application and it used to fetch the required data. We just used to read the required fields by forming a URL by passing username , password and search parameter (DEA number). The same URL (with parameters ) could also be hit from browser directly to see the results. It was a simple GET request:
{URL url = new URL(
"http://www.deanumber.com/Websvc/deaWebsvc.asmx/GetQuery?UserName="+getUsername()+"&Password="+getPassword()+"&DEA="
+ deaNumber
+ "&BAC=&BASC=&ExpirationDate=&Company=&Zip=&State=&PI=&MaxRows=");
Document document = parser.parse(url.toExternalForm());
// Ask the document for a list of all <sect1> tags it contains
NodeList sections = document.getElementsByTagName("DEA");
//Followed by a loop code to get each element by using sections.item(index).getFirstChild() etc.
}
Now, the website URL has got changed to following:
https://www.deanumber.com/RelId/33637/ISvars/default/Home.htm
I am able to login to the URL with credentials , go to the search page , enter the DEA number and search. The login page comes as a pop-up once I click 'Login' link on home page. Also, the final result comes as a pop-up. This is a POST request so I am unable to form the complete URL which I could use in my code.
I am not an expert in Web Services , but I think I need a web service URL like the one mentioned in the code above. Not sure how to get that !! Even if I get the URL , I am not sure how to perform the login through Java code and search the DEA number.
Also, it would be great if I could validate the URL manually before using in Java. Let me know if there is any way.
Or, in case there is any alternate approach in Java; kindly suggest.
Thanks in advance.

First of all, the previous approach provided by the website was completely wrong and insecure, because it passes the username and password as querystring parameters in plain text. I think, they would have realized this thing and changed their way of authentication.
Also, it looks like that they have restricted the direct URL based requests from the client applications like yours. For such requests from clients, they have published the web services. Check this link. They also have mentioned the rates for web service request counts.
So, you may need to open a formal communication channel to get authentication and other details to access their web services for this purpose. Depends on what they use for web service client authentication, you may code your client to access the web services.
I hope this helps.

Fetching Facebook User Access Token Callback

I am trying to fetch Facebook user access token as in the question title.
I configured my application, I am sending request to:
redirect:https://www.facebook.com/dialog/oauth?client_id="+appId+"&redirect_uri="+REDIRECT_URI+"&response_type=token
and I always got response where there is a hashtag before first parameter:
/auth/fb/callback/?#access_token=blablabla
Does anyone know why Fb is keep adding the # before access_token??
I have hard time to parse this from HTTP request, as Spring shows me 0 GET parameters.
Is it possible to avoid this situation or parse with #???

Does anyone know why Fb is keep adding the # before access_token?
Because you asked for it, by using response_type=token. You actually want to ask for a code instead.
https://developers.facebook.com/docs/facebook-login/manually-build-a-login-flow#logindialog

Android, AccountManager and OAuth

I'm sure this is basic and I'm missing something. I've read through other answers on SO, I've googled, I've read resources and I just can't wrap my head around what I need to do.
I'm trying to figure out how to write an app that connects to Twitch's API, specifically how to authenticate with Twitch's api. Their documentation is here: https://github.com/justintv/Twitch-API/blob/master/authentication.md
I've created an app and stored my keys.
Now comes the part where I want my user to click a button which launches the authentication on their website. From what I can tell I do this by using an AccountManager. Except... I can't figure out what I'm supposed to do.
Here's the excerpt I've found online:
AccountManager am = AccountManager.get(this);
Bundle options = new Bundle();
am.getAuthToken(
myAccount_, // Account retrieved using getAccountsByType()
"Manage your tasks", // Auth scope
options, // Authenticator-specific options
this, // Your activity
new OnTokenAcquired(), // Callback called when a token is successfully acquired
new Handler(new OnError())); // Callback called if an error occurs
According to twitch's documentation I want to send the user to:
https://api.twitch.tv/kraken/oauth2/authorize
?response_type=code
&client_id=[your client ID]
&redirect_uri=[your registered redirect URI]
&scope=[space separated list of scopes]
&state=[your provided unique token]
And I simply have no idea how these two things need to be combined.

Firstly, I recommend to read the OAuth2 RFC. This should cover everything you need to know.
The AccountManager code snippet won't help you much unless there already is an app that provides authentication for Twitch. If that's not the case you either need to use an existing OAuth2 library or implement your own.
You could write your own AccountAuthenticator but that's a different challenge (and you still need some kind of OAuth2 client).
Doing it yourself is not that hard, see below.
Steps to implement it yourself
Twitch recommends to use the "Implicit Grant Flow" for mobile apps. That's what I'm going to describe below.
1. Get a client ID
Register your app as outlined in Developer Setup to get a client ID
As redirect URI you can use something like https://localhost:12398/, the actual port doesn't really matter.
2. Build the authentication URL
In your client app you need to construct the authentication URL like so:
https://api.twitch.tv/kraken/oauth2/authorize?
response_type=token&
client_id=[your client ID]&
redirect_uri=[your registered redirect URI]&
scope=[space separated list of scopes]
Apparently [your client ID] should be replaced by the client ID you've received from Twitch, same goes for [your registered redirect URI] (that's the URL above, i.e. https://localhost:12398/). [space separated list of scopes] is the list of scopes (i.e. features your want to access), see Scopes. Make sure you URL-encode the parameter values properly.
Assuming your client ID is 123456 and the scopes you need are user_read and channel_read your URL would look like this:
https://api.twitch.tv/kraken/oauth2/authorize?
response_type=token&
client_id=123456&
redirect_uri=https%3A%2F%2Flocalhost%3A12398%2F&
scope=user_read%20channel_read
Note that you should also pass a state parameter, just use a randomly generated value. You can also append the (non-standard) force_verify parameter to make sure the user actually needs to log in each time (instead of continuing a previous session), but I think you can achieve the same by clearing the cookie store (given that you open the URL in a webview in the context of your app) before you open the login page.
With a random state the URL would look like this:
https://api.twitch.tv/kraken/oauth2/authorize?
response_type=token&
client_id=123456&
redirect_uri=https%3A%2F%2Flocalhost%3A12398%2F&
scope=user_read%20channel_read&
state=82hdknaizuVBfd9847guHUIhndzhuehnb
Again, make sure the state value is properly URL encoded.
3. Open the authentication URL
Ideally you just open the URL in a WebView inside of your app. In that case you need to intercept all request to load a new URL using WebViewClient.shouldOverrideUrlLoading
Once the client is redirected to your redirect URL you can close the webview and continue with step 4.
Theoretically it's possible to utilize the default browser to do the authentication, but I would have security concerns since an external app could learn about your client ID and the access token.
4. Extract the access token
The actual URL you get redirected to in step #3 will have the form:
https://[your registered redirect URI]/#access_token=[an access token]&scope=[authorized scopes]
or to pick up the example
https://localhost:12398/#access_token=xxx&scope=user_read%20channel_read
Where xxx is the actual access token.
If you passed a state it will be present like so:
https://localhost:12398/#access_token=xxx&scope=user_read%20channel_read&state=82hdknaizuVBfd9847guHUIhndzhuehnb
All you have to do now is to parse the (URL encoded) access token, scope and state. Compare the scopes and state to the ones that you actually sent. If they match you can start using the access_token to authenticate.
Note According to the OAuth2 RFC, the response URL MUST also contain a token_type and it SHOULD contain an expires_in duration in seconds.
Once you received the access token you can use it to authenticate as described here.
Access tokens issued by the Implicit Grant Flow usually expire after a certain time and the user needs to authenticate again. The Twitch documentation doesn't mention any expiration time, so it's possible that the token is valid forever. So make sure your app doesn't store it or store it in a secure way (like using Android's key store provider to generate and store a key to encrypt the access token).
If the implicitly issued access token expires you could consider using the "Authorization Code Flow". That's quite similar but it contains an additional step to receive the access token and a "refresh token" that can be used to renew the access token. I leave it up to you to figure out how that works.

Errors using signpost api for oauth in java

I have been trying for months to get access to a certain api (which has almost no documentation) to work using signpost. The api has oauth 2.0 authentication. The problem is that I have never used oauth before. But I have spent a long time reseaching so I think I have a functional understanding of how it works. I thought that using the handy singpost api it wouldn't be too much trouble to hack through it, but alas I have encountered a wall. The api docs are here:
https://btcjam.com/faq/api
It gives three URLs that are needed for the oauth authentication, which I am writing as java here for consistency with some code below:
String Authorization= "https://btcjam.com/oauth/authorize";
String Token ="https://btcjam.com/oauth/token";
String Applications = "https://btcjam.com/oauth/applications";
I have an application with a name, key, and secret. I also have set my callback URL to be the localhost, i.e.
http://localhost:3000/users/auth/btcjam/callback.
Now, as I am reading the signpost docs, it tells me that in order to request an access token, I need to do something like the following:
OAuthProvider provider = new DefaultOAuthProvider(
REQUEST_TOKEN_ENDPOINT_URL, ACCESS_TOKEN_ENDPOINT_URL,
AUTHORIZE_WEBSITE_URL);
String url = provider.retrieveRequestToken(consumer, CALLBACK_URL);
However, I am unsure exactly what to put for the URL's in these various spots, and I am getting errors. The problem is that The names of the URLs required above do not correspond to the URLs given. The "authorization" and "callback" URLs seem to match up nicely, but I am not sure how the URLs "REQUEST_TOKEN_ENDPOINT_URL" and "ACCESS_TOKEN_ENDPOINT_URL" required in the signpost docs correspond to the URLs given by the api docs on the serverI am trying to access. Of course, there are only two possible permutations, but when I try them both I get two different errors:
"Authorization failed (server replied with a 401). This can happen if the consumer key was not correct or the signatures did not match."
"Communication with the service provider failed: URLDecoder: Illegal hex characters in escape (%) pattern - For input string: " 1""
Could someone please help explain what might be going on here? Am I very close to getting this to work or do I have to take a bunch of steps back?
Any help is much appreciated.
Thanks,
Paul