Calling a web service using URL with complex parameters - asp.net

I have web services that work fine using SOAP, but today I received a request to call the web services using the URL.
So, instead of consuming the service, they want to call http://servicename/ProductEnq.asmx/ProductEnqByCodeWithLogin?Code=123456789&Username=user&Password=bubbles
I found that the "basic" calls work 100%, i.e. when the params are all strings, like the call above. This method returns a complex type.
Where I get stuck is that I have another method that expects a List of strings as parameter together with some other params.
No matter how I try to get the list to be populated, the page always returns "System.InvalidOperationException: ProductEnqByMultipleCodesWithLogin Web Service method name is not valid."
Please note that this call works 100% when called from my application or WebService Studio.
Any hints on if this is possible, or should I just convince the client to use SOAP?
Thank you.
Jaco

Related

Risks of AJAX calls to asmx

Currently working on an ajax call to an ASP web service (.asmx).
In a situation where I POST to the url/.asmx/WebMethod, am I exposing information of any kind?
In the 'WebMethod' I am running a PostJsonAsync that calls an API and passes along a json string.
As I am still learning, I've been told that calling any public [WebMethod] exposes the code, but I am not sure how that is possible.
Is it possible at all for a user to access the WebMethod server-side code that I have and peek into the API calls that are available?
I've attempted some minor security methods.. We are working with Sitefinity CMS. What I did was call a WebMethod that receives the CurrentUserIdentity and returns a GUID. If the current user is logged in, it returns a valid Guid, if not it returns a Guid full of zeros.
Then, I call the WebMethod containing my API call and post a json object along with the valid or invalid GUID. The server-side WebMethod code will then verify if the GUID is valid and continues based on if a UserProfile can be generated.
To me, this seems to be secure, but I've been told that this still leaves the WebMethod exposed as well as the API. I am however just not understanding what is exposed and what can be used.
If anybody can direct me to any resources that has more information on this, or if anybody can advise me on WebService security, I would appreciate it.
Thanks in advance.
If you're calling the methods via AJAX, then they are exposed to the public...and can be called by anything that can make a call to your server. That being said, there's nothing wrong with it unless you're doing something that's easily abused.
In your particular case, it sounds like the code is accepting a GUID that is assumed to have come from the first API call. If that's really the case, you may want to rethink how the mechanism works. Adding authentication checks for each method that needs to be restricted may be a better solution.

Securing web method on a public web app

I have a public web app that calls ASP.NET web method in an ASMX file, located in the same site folder in IIS. But, to prevent bots to ping the service directly, we'd like to secure the API so that only our HTML 5 client page can access it. Do you have a suggestion on how should I implement this kind of thing ? Not too much, just a simple mechanism that won't take a week of testing please. Doesn't have to be a 100% full proof method since it is public data and the API just pumps data out, not inserting anything. Just something to limit possibilities of DDOS attack on the API.
The way I've tackled this in the past is with a custom header.
Essentially if your web page is using some form of AJAX call to call back to your services layer, then you can use something like:
xhr.setRequestHeader('custom-header', 'value');
where 'xhr' is an XML Http request that you've built in Javascript
of course you could also take the much easier route of just adding a parameter to your calls query string, EG:
in your ajax call, request:
http://my.services/service.asmx?somesecretkey=foobar
instead of just
http://my.services/service.asmx
Then you can just use the request's query string collection server side to see if it's present or not, and refuse the connection if it's not.
You could even go so far as providing some seed value in the data passed to the page in the first place, then use that seed value to create a unique value (one the server can also calculate) that is returned back in your request to the server.
Doing it that way would provide a slightly higher level of security, as the values would be semi random and not easy for a bot to guess.
Bear in mind also, that if you control the calling page, and you are doing this by ajax, you can also put this key in your post variables collection too so it doesn't have to be visible in the get request.

Accessing workflowArguments in a hosted workflow

We are mixing workflows, a workflow using receive activity's more at the end. But at the start we want to pass in some arguments (not using a receive activity!)
Our workflows are already being created and resumed using a dynamic endpoint with IWorkflowCreation and a class derived from WorkflowHostingEndpoint. In the OnGetCreationContext the creationgContext is filled with WorkflowArguments and the workflow runs. At a later part the receive activity's are creating a bookmark which can be resumed with a message. All seems nice.
But in a xamlx there are no WorkflowArguments, i understand why, except that i want them anyway. I though about an activity in which i can write some code to get the Arguments myself, but i do need some help here.
Or is there another way to pass along the WorkflowArguments into a xamls without using Messaging?
You can't pass arguments into a starting workflow service except through the SOAP message that starts it. But there is nothing preventing you from reading any properties in your workflow service. So it is perfectly fine to do read settings or something similar instead of passing them in at startup.
We have solved this exact situation by creating another WCF service which sits alongside our xamlx service on a slightly different url (e.g. /WorkflowMetadata) and this is where we implement a service method that returns a dictionary of string, type.
In the implementation of this service we simply read the xamlx and determine the arguments.
This is what we use to interrogate a target workflow in an activity designer when creating something like a launch-workflow activity.
Creating an activity will not work as that activity will need an instance in order to run. All you want is some metadata about the xamlx service. And if you are using a WorkflowCreationEndpoint to construct a creation context then you are probably only allowing a dictionary of string, object as the start parameters. Therefore standard metadata will not work. This left us with the only option being to provide another service beside the workflow which serves metadata.
Background here: http://blog.petegoo.com/index.php/2011/09/02/building-an-enterprise-workflow-system-with-wf4/

What happens if web services changes the parameters?

Say i'm having a web service that accepts two arguments and that is being called/consume in my application. Now after some time, the web service changes and accepts three arguments, hence in my application, would that be throwing an error, or i need to just update the web reference, or i need to recreate a web serivce or would that be working fine?
Let me know if any doubts
Thanks!
You could add optional parameters where if a parameter value isn't given to the method a default value is used.
From a "pure" architectural aspect, you should never change the signature of a method of a service once it's in use. You should version by creating a new method with a different namespace. But staying pure is sometimes difficult to do.
In your case you need to update the Web reference in the client application and then modify the code to pass in the appropriate parameter to the method in the service proxy.

Cannot serialize interface System.Collections.Generic.IDictionary

What does this mean? google search turns up nothing.
The curious thing is that I get this message when I try to access the web service directly in the browser http://localhost/Myservice/Service.asmx
But when I use the service (I invoke it inside my Jquery code) it works perfectly. Very curious detail....
This might be because you have a function in your web service that returns an interface, or that returns an object that contains a property or function using an interface. For further details on interfaces and serialization take a look at this SO question.When you use your web service from javascript you only call one or more specific functions, but browsing on your web service with internet explorer forces a request of a whole wsdl description of your the web service with all its functions. I guess that is why it worked for the first case and not for the second.

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