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RespondPageWithJSRedirect() - where is this defined?

Hi,

I am trying to set-up a Dropbox connection in .NET (Xamarin to be precise). I am following http://dropbox.github.io/dropbox-sdk-dotnet/html/T_Dropbox_Api_DropboxOAuth2Helper.htm. When I start typing in "RespondPageWithJSRedirect()" it isn't being detected anywhere by intellisense (Visual Studio 2017). I've got all the usings that have been specified on the quoted page, so I'm either mssing a nuget, or another using, or something like that. When I search for this string on the gitgub page https://github.com/dropbox/dropbox-sdk-dotnet/blob/master/dropbox-sdk-dotnet/Dropbox.Api/DropboxOauth2Helper.cs it only finds 2 instances - a comment and the call itself. Where is this defined? What do I need to add?

thanks,

Donald.

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Accepted answers

Greg-DB

Apologies for the confusion! The SDK doesn't offer an implementation of RespondPageWithJSRedirect. That's intended to be whatever page you wish to show to the user at that point in the process. (E.g., it can optionally contain a message for the user, and whatever branding/styling you want for your app.)

Here's where this is done in the example, and here's the HTML page, including the minimum JavaScript necessary, used for that example.

All comments

Greg-DB

Here's where this is done in the example, and here's the HTML page, including the minimum JavaScript necessary, used for that example.

donaldp

Hi Greg,

Thanks for that. Sorry for slow response, but was away for Xmas, and now spent a while trying to get it working before replying. Making progress, but stuck now (and not getting as far as the RespondPageWithJSRedirect() code to see if that works unfortunately :-( ).

On Win10 I get as far as the System.Diagnostics.Process.Start(authorizeUri.ToString()); line, and get Exception thrown: 'System.ComponentModel.Win32Exception' in System.Diagnostics.Process.dll (Googling this not proving very helpful).

Tried on my Android phone when I got stuck on Windows, and only got to the previous line - http.Start(); - though I'm not sure what the problem is as Android throws out an awful lot of messages and I'm not sure what it is I'm looking for there?

BTW I'm still not sure I have the redirectUri set-up correctly (and could be the problem to begin with here) - responses here always amount to "you can put whatever you want there", which isn't helpful if you don't know what to put there to begin with! I'm using this (as per the code on your page)...

private const string LoopbackHost = "http://127.0.0.1:52475/";
private readonly Uri RedirectUri = new Uri(LoopbackHost + "authorize");
private readonly Uri JSRedirectUri = new Uri(LoopbackHost + "token");

So on Dropbox in the redirectUri, should that be "http://127.0.0.1/authorize", or "http://127.0.0.1:52475" or "http://127.0.0.1:52475/authorize", or...? I'm also not sure how to check on unused ports if it comes to that (I found a command, but the command doesn't say whether it's listing used or unused ports! And I don't know if the above message is because that port is busy or something else).

thanks,

Donald.

Greg-DB

Are you getting that error when trying to run the "SimpleTest" sample app? Have you made any modifications (other than plugging in an app key)? I just tried it in Visual Studio 2017 on Windows 10 and I didn't get that error unfortunately. Is there any other output in the log?

To clarify, are you also trying to run the "SimpleTest" on Android? That sample wasn't written for Android, nor does the .NET SDK itself officially support Android.

Based on that code snippet, the redirect URI would be "http://127.0.0.1:52475/authorize".

I can't offer insight on checking the ports on a system though, as that's not part of Dropbox.

donaldp

Hi Greg,

> Are you getting that error when trying to run the "SimpleTest" sample app?

I was coding my own test app from scratch, but following those 2 examples, so the answer is yes, kinda. Your remark has made me think I'll just try running the whole SimpleTest as is, and see if that works for me as is... but as I've found previously (like missing usings), there's a bunch of details that have been left out. See below for all the error messages I got.

> Is there any other output in the log?

Lots of messages, as usual, but only 2 errors. The 2nd was with the httplistener, and was further down, so may have been a flow-on from the first error. trying to fix the 1st error 1st, and see if that also fixes the 2nd error.

> To clarify, are you also trying to run the "SimpleTest" on Android? That sample wasn't written for Android, nor does the .NET SDK itself officially support Android.

As mentioned, I'm using Xamarin, which supports UWP, iOS and Android (plus some other platforms too). Coding is done in C#/.NET, and Xamarin takes care of the platform stuff in the background. They do have a Xamarin.Dropbox.Api - apparently they had to do a few hacks to make the Dropbox.Api work with Xamarin (maybe related to the fact that .NET doesn't officially support Android?) - and that is the one I'm using. It's available in nuget.

> Based on that code snippet, the redirect URI would be "http://127.0.0.1:52475/authorize".

Thanks.

Severity Code Description Project File Line Suppression State
Error CS0246 The type or namespace name 'WebRequestHandler' could not be found (are you missing a using directive or an assembly reference?) SimpleTest \Users\Donald\Source\Repos\SimpleTest\SimpleTest\SimpleTest\App.cs 67 Active
Error CS0103 The name 'Settings' does not exist in the current context SimpleTest \Users\Donald\Source\Repos\SimpleTest\SimpleTest\SimpleTest\App.cs 220 Active
Error CS0103 The name 'Settings' does not exist in the current context SimpleTest \Users\Donald\Source\Repos\SimpleTest\SimpleTest\SimpleTest\App.cs 224 Active
Error CS0103 The name 'ApiKey' does not exist in the current context SimpleTest \Users\Donald\Source\Repos\SimpleTest\SimpleTest\SimpleTest\App.cs 232 Active
Error CS0103 The name 'Settings' does not exist in the current context SimpleTest \Users\Donald\Source\Repos\SimpleTest\SimpleTest\SimpleTest\App.cs 261 Active
Error CS0103 The name 'Settings' does not exist in the current context SimpleTest \Users\Donald\Source\Repos\SimpleTest\SimpleTest\SimpleTest\App.cs 262 Active
Error CS0103 The name 'Settings' does not exist in the current context SimpleTest \Users\Donald\Source\Repos\SimpleTest\SimpleTest\SimpleTest\App.cs 264 Active
Error CS1061 'FullAccount' does not contain a definition for 'RootInfo' and no accessible extension method 'RootInfo' accepting a first argument of type 'FullAccount' could be found (are you missing a using directive or an assembly reference?) SimpleTest \Users\Donald\Source\Repos\SimpleTest\SimpleTest\SimpleTest\App.cs 343 Active
Error CS1061 'DropboxClient' does not contain a definition for 'WithPathRoot' and no accessible extension method 'WithPathRoot' accepting a first argument of type 'DropboxClient' could be found (are you missing a using directive or an assembly reference?) SimpleTest \Users\Donald\Source\Repos\SimpleTest\SimpleTest\SimpleTest\App.cs 352 Active
Error CS0426 The type name 'Root' does not exist in the type 'PathRoot' SimpleTest \Users\Donald\Source\Repos\SimpleTest\SimpleTest\SimpleTest\App.cs 352 Active
Error CS1061 'FullAccount' does not contain a definition for 'RootInfo' and no accessible extension method 'RootInfo' accepting a first argument of type 'FullAccount' could be found (are you missing a using directive or an assembly reference?) SimpleTest \Users\Donald\Source\Repos\SimpleTest\SimpleTest\SimpleTest\App.cs 352 Active
Error CS0246 The type or namespace name 'PathRootException' could not be found (are you missing a using directive or an assembly reference?) SimpleTest \Users\Donald\Source\Repos\SimpleTest\SimpleTest\SimpleTest\App.cs 355 Active

Greg-DB

I see, thanks. I do recommend starting from the unmodified SimpleTest on a supported platform as a reference, as that should work out of the box with no modifications (beyond plugging in your own app key). That's what I tested, and it worked for me.

Anyway, unfortunately the SDK isn't officially supported in Xamarin, so we can't offer support for that platform. I'll send this along as a feature request for official support for that though. We can't officially support that third party library either of course, as that's maintained by a third party.

donaldp

Dropbox won't let me register another app called SimpleTest so that I can get my own apikey for it - can you supply the apikey for it? Or if I use one I have already, will that work if the names don't match? I've tried to work around this restriction, with no success so far. i.e. tried to clone SimpleTest, calling it something different in the process, however when I click "fork", it forks the whole .net library, not just SimpleTest itself. Not sure how to get around this restriction on unique app names (or that it won't let me fork just that directory).

DBX_Robert

The reason you cannot register a duplicate Dropbox App with the same name is because Dropbox requires App names be unique. I do not believe you need to create a new Dropbox app for your use case. It is okay if the name of your app registered with Dropbox and the name of the .NET project do not match.

donaldp

Hi Greg,

As per Robert's advice, I put my own Apikey into SimpleTest, and ran it on Win10 in VS2017 (I also had to uncomment one of the Apikey references, so you may want to uncomment that in your repo. i.e. it got updated when I updated the main reference, but that line was still commented out). I get as far as the "Reset Settings?" prompt coming up, which is a start! Then, after answering, I got "Exception thrown: 'System.Net.HttpListenerException' in System.dll". Thinking this MAYBE the redirectUri not matching, I had a look through the code, and then added the corresponding setting "http://localhost:5000/admin/auth" to my redirectUri's. I also tried adding a trailing slash, as I'd seen along the way somewhere that this was required, but that didn't help either.

When I Google the error, it says...

"This exception is thrown by the HttpListener class and its associated classes when an error occurs during initialization of the HttpListener or while creating or sending a response to an HTTP request. For example, this exception is thrown if the HttpListener attempts to register a Uniform Resource Identifier (URI) prefix that is already registered.

Associated Tips

Make sure you are not attempting to register a URI prefix that is already registered.
If the URI prefix is already registered, this exception will occur"

I checked that port 5000 is not currently in use. Not sure what else to try with this? I've exhausted all the things that I can think of. Is there maybe something not set-up correctly somewhere?

Greg-DB

Thanks for the information. You shouldn't get that particular exception for a mismatch with the registered OAuth 2 redirect URIs for your app, so it must be something else, such as a potential port issue as you mentioned. If you attempt to use a redirect URI that isn't registered for your app, you'd see an error on the Dropbox web page itself. (That's only validated once the user hits the www.dropbox.com/oauth2/authorize... page with the client_id and redirect_uri parameters.)

Anyway, I'm also testing with Visual Studio 2017 on Windows 10, and I can't reproduce this HttpListenerException with the SimpleTest sample app. Can you print out the InnerException or Message in case it has more specific information on the issue?

One point of clarification though, the SimpleTest app uses the local port 52475 for the redirect URI, not 5000. Based on your mention of "http://localhost:5000/admin/auth", it sounds like you're actually looking at UniversalDemo, not SimpleTest.

If you are running the SimpleTest sample (as it sounds like you are, based on your reference to the "Reset Settings?" prompt), please check port 52475 is free (instead of 5000).

(And thanks for the note about uncommenting the ApiKey line. I'll ask the team to do that.)

donaldp

Thanks for further explanation on the process - not having done OAuth2 before I wasn't sure what to expect where or when. With more time spent on the host issue, this led to PROGRESS! :-) The suggestion on the website for a redirectUri is "https://localhost", and what I've found - in the end (cos at first I changed the code to match the website, not the other way around!) - was that the program ONLY works if you include the port and "authorize" (so "https://localhost" won't actually work, even if you had https://localhost in the code). I suggest you change the hint text on the website to include a port number and "authorize" (even if someone goes and changes them themselves. Situation not helped by freqent mentions of "you can put whatever you want there" - no you can't. If you don't include a port number it doesn't work. Ditto for the "authorize" if it's in your code. The only optional bits are http or https:, localhost or 127.0.0.1 - they all work either way. At least I've solved that now!).

So, went through the authorisation, and now the SimpleTest app is getting stuck a bit further on, at var context = await http.GetContextAsync();. Not crashing, just hung, therefore no error messages at all. Not sure what I need to do to get this line working? (I've let it sit there for several minutes now and still no sign of a response)

Note, the app was opening up a tab on my already-open browser. Just in case this was an issue, I closed my browser and reran the program (so it had a new browser all to itself), but it still hung. I can see the token there in the URL (yay! ;-) ), but it's not making it's way past that. :-(

Also, you're right. I was runing SimpleTest,but when I clicked on it to check the host I had accidentally clicked on the one underneath! Oops.

Greg-DB

I see, thanks for the feedback!

For the current issue, since you modified the code, please revert to the original SimpleTest code (or switch to a fresh copy). You should only have to add your app key; no other code changes are necessary for that sample.

It sounds like the app is hanging waiting on the user to come back to the previously configured redirect URI, but you may have accidentally changed what that path is, meaning it will never match.

donaldp

Woo hoo! Success! :-)

> you may have accidentally changed what that path is, meaning it will never match

It was actually getting stuck at the line before the one you have highlighted, but in any case loading in a fresh copy, and knowing what to put into the website now, got it all working. :-)

Now that we've got that little proof of concept done on my computer, I can get back to MY program and try and work out why IT'S not working (but now I can compare directly to SimpleTest, sicne I know that works). Will let you know how I go.

BTW, I still recommend you fix up that hint text (and be more specific with people when they ask what needs to go there). It DOES NOT work unless you include a port (and in the case of SimpleTest, you must also include the authorize). A proper example in the hint (i.e. showing that you need to the port number too) would be helpful.

Thanks! :-)