consuming an XML WCF REST webservice from JavaScript
javascript, wcf, web-services
Solution
I suppose that you use ASP.NET 4.X.
WCF 4 supports automatic format selection based on HTTP "Accept" and "Content-Type" headers of requests. One specify `automaticFormatSelectionEnabled="true"` attribute in `web.config` file:
<configuration>
<system.serviceModel>
<standardEndpoints>
<webHttpEndpoint>
<!-- the "" standard endpoint is used for auto creating a web endpoint. -->
<standardEndpoint name=""
helpEnabled="true"
automaticFormatSelectionEnabled="true"/>
</webHttpEndpoint>
</standardEndpoints>
</system.serviceModel>
</configuration>
See "Message Format Selection" part of the article and the article for more information. You can combine automaticFormatSelectionEnabled attribute with defaultOutgoingResponseFormat (which you can set to "xml" or "json", default is already "xml"). You can specify the attributes only for one specific endpoint instead of usage `standardEndpoint` as in the example above.
So your existing WCF service will just provide JSON data for JavaScript requests and still returns XML data for other client if you would use the corresponding WCF configuration.
Problem
I have a WPF application that exposes a REST WCF service (via `WebServiceHost`) with a contract that looks something like this (simplified): ``` [ServiceContract] public interface IItemServiceContract { [WebGet(UriTemplate = "Items/{id}")] Item GetItem(string id); [WebGet(UriTemplate = "Items")] IEnumerable<Item> GetItems(); [WebInvoke(UriTemplate = "Items", Method = "PUT")] IEnumerable<Item> CreateItems(IEnumerable<Item> list); } ``` When I navigate to `http://localhost:8070/Contoso/Services/Items/ItemService/Items` with a browser, I get a response that looks something like this: ``` <ArrayOfItem xmlns="http://schemas.datacontract.org/2004/07/Contodo.Services.Items" xmlns:i="http://www.w3.org/2001/XMLSchema-instance"> <Item> <ItemState> <Comment i:nil="true"/> <DeactivationTime>0001-01-01T00:00:00</DeactivationTime> <Id>18f1a5e4-a94a-4f37-a533-3a75a10e7373</Id> <IsSpecial>false</IsSpecial> </ItemState> <ItemTypeId>10</ItemTypeId> <HelpInfo/> <Identity>Ident1</Identity> <AdditionalInfo> <?xml version="1.0" encoding="utf-16"?> <Content> <SpecialContent /> </Content></AdditionalInfo> <TextParameter>kjhdfsjh kj dkfjg kj</TextParameter> <UserName i:nil="true"/> </Item> </ArrayOfItem> ``` What would be an easy and friction-free approach to consume this service with JavaScript? How can a client quickly build the http requests and the appropriate XML for it? I am fairly in the Html5/javaScript world but in a C# I would have an API in place that is centered around the `Item` object that gets serialized to XML. But is that the way to go for here? Update: Based on the first comments and answers, it seems that XML is not the ideal format for a JavaScript/webbrowser consumer but I can't just change the format to JSON because that would probably break existing clients that already rely on this XML format. So ideally I would do REST content type negotiation and put/get JSON or XML. But can this be done with WCF REST services?