CODEWITHSUNDEEP
c#.netweb-services
Christian
Christian

Reputation: 33

Not sure how to send complex data using Web Services

I've looked at quite a few of the questions on the site, but I'm still having trouble fulling understanding where to begin.

I've never done anything with webservices before, so bear with me.

The current project I've been assigned is to write a webservice that queries a database and returns the data back to the client. (using .NET 2008 programming in C#)

So far, I've been able to do basic data types no problem, but I'm not 100% sure where to go from there. I've been returning an XmlDocument type, but I'm not sure that that's the best way, or even the correct way to do it.

Currently creating an ASP.NET Web service, though it's been suggested I use a WCF Web service.

Can anyone shed light on where to go from here? Or perhaps a a link to a tutorial on sending and recieving large amounts of data via webservices?

EDIT: The answers are great so far, but I'm still not 100% sure how to answer. I think the webservice will be interacted with a combination of client programs, but also websites, if that is all possible... That's how new I am to this.

Upvotes: 3

Views: 2527

Answers (5)

anaconda
anaconda

Reputation: 1092

The best way to send data back to client it's throught xml, because almost all languages know how to handle xml document.

If you want to return something that it's in some way language dependent is't not worst to implement if you want your web service to be implemented using virtually all languages posible.

Another posibility is to return json objects.

Upvotes: 0

Mike Webb
Mike Webb

Reputation: 9003

There are two ways that I have implemented this using a regular ASPX.NET web service:

  1. Have the same underlying object libraries on the client and the server and functions to translate the data from the web service object to the client object.

  2. Have the same underlying object libraries on the client and the server and pass data to/from the server as a string representation of the data object (usually XML format, but could be JSON or another similar format)

The first option I found is VERY cumbersome. The web service will claim that its versions of the libraries are unique, even if you have the same classes/objects on both the server and the client. Even if the namespace is the same, the object returned from the web service will have the web service namespace in it somewhere, so you have to write functions to convert them. I know of a way to fix this, but it is not worth the effort, at least not for me.

The second option is the one I am using right now. I again have one library on both client and server. It has objects that get and hold data from the database. I then have generic utility functions that serialize objects to and from XML strings. When I send data from the server I serialize it to an XML string on the server and deserialize it at the client. I do the reverse when sending data to the server. I also break up large amounts of data being passed to/from the web service to reduce errors and data transfer time.

WCF may be better. Never used it. But the above is what I have done with standard web services.

Upvotes: 0

David Hoerster
David Hoerster

Reputation: 28701

Depending on the structure of the data that you're sending back to the client, I wouldn't recommend using XmlDocument as the return type. It will add a lot of unnecessary bulk to your response.

You really didn't state the protocol that you want to support, but if you're transporting data via HTTP, then sending your data back to the client as a JSON-formatted string would streamline it better.

You can define that you're returning your complex type formatted as JSON like this:

[WebGet(ResponseFormat=WebMessageFormat.Json, UriTemplate="GetComplexObject/{id}")]
public MyComplexType GetComplexObject(int id){
  //do work to get your object
  return myObject;
}

WCF will take care of serializing your object as JSON if MyComplexType is defined as a DataContract...

[DataContract]
public class MyComplexType{
  [DataMember]
  String Name {get;set;}
}

If you're looking for REST-ful services, then WCF is probably the preferred approach using the WebHttp functionality.

The WCF team put together a great series of walk-throughs on using WCF WebHttp (which is new to .NET 4). They assume a little knowledge of web http programming, but they're pretty good and hopefully help put you on the right track.

I hope this helps!! Good luck.

Upvotes: 2

smartcaveman
smartcaveman

Reputation: 42246

If you decide to use WCF there is a tutorial available at : http://dotnetslackers.com/articles/ajax/JSON-EnabledWCFServicesInASPNET35.aspx .

In general, this article gives a walk through of building an ASP.NET web service that sends JSON.

JSON is faster than XML, and is becoming a standard for most new web services. I highly recommend the JSON.NET library for JSON serialization.

Upvotes: 0

Ryan Bennett
Ryan Bennett

Reputation: 3432

http://msdn.microsoft.com/en-us/library/ms733127.aspx

WCF uses this concept of a data contract - which provides serialization help on complex objects.

Upvotes: 2

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