// flag below because it's a *pain* to break inside this routine unless it was intended.
// we want the exceptions from here to considered the root for the debugger to land.
/// <summary>
/// Executes a JSON based REST rpc call
/// </summary>
/// <param name="baseUrl">The url to use</param>
/// <param name="args">Arguments to append to the url, represented as a simplified json object (only holds scalar values)</param>
/// <param name="payloadJson">The JSON to send as part of the request body</param>
/// <param name="timestampField">If specificed, indicates a field to insert a timestamp into. This timestamp represents the time the object was last fetched (either from the file cache or from the server)</param>
/// <param name="httpMethod">Set this to use a custom HTTP method (like DELETE)</param>
/// <param name="fixupResponse">An optional custom routine that can massage the JSON returned into a more acceptable form. This is useful if the data from the server needs to be adjusted prior to anything else.</param>
/// <param name="fixupError">An optional custom routine that can massage the JSON error object returned into a more acceptable form. This is useful if the error from the server needs to be adjusted prior to anything else. You may need to specify this to get the <see cref="JsonRpcException" /> to work properly.</param>
/// <param name="cache">Indicates whether or not a file cache should be used for requests. The in memory cache is only on a per-thread basis. The file cache stores by URL and is global. The cache is very aggressive.</param>
/// <returns>The JSON returned in the response body.</returns>
/// <remarks>Exceptions are expected to have JSON in the response body. This JSON is used as the data for the exception. The exception thrown currently uses a simple heuristic to figure out what the relevant fields are. Usually however, you'll get the data using the Json property of it.</remarks>
//[DebuggerNonUserCode]
public static object Invoke(
string baseUrl,
IDictionary <string, object> args = null,
object payloadJson = null,
string timestampField = null,
string httpMethod = null,
Func <object, object> fixupResponse = null,
Func <object, object> fixupError = null,
JsonRpcCacheLevel cache = JsonRpcCacheLevel.Conservative)
{
HttpWebRequest wreq = null;
HttpWebResponse wrsp = null;
var url = GetInvocationUrl(baseUrl, args);
wreq = WebRequest.Create(url) as HttpWebRequest;
wreq.KeepAlive = true;
wreq.Pipelined = true;
wreq.AllowAutoRedirect = true;
RequestCacheLevel cp = RequestCacheLevel.Default;
switch (cache)
{
case JsonRpcCacheLevel.None:
cp = RequestCacheLevel.NoCacheNoStore;
break;
case JsonRpcCacheLevel.Conservative:
cp = RequestCacheLevel.Revalidate;
break;
case JsonRpcCacheLevel.Aggressive:
cp = RequestCacheLevel.CacheIfAvailable;
break;
}
wreq.CachePolicy = new RequestCachePolicy(cp);
if (null != payloadJson)
{
if (string.IsNullOrEmpty(httpMethod))
{
wreq.Method = "POST";
}
else
{
wreq.Method = httpMethod;
}
wreq.ContentType = "application/json";
using (var sw = new StreamWriter(wreq.GetRequestStream()))
{
JsonObject.WriteTo(payloadJson, sw, null);
sw.Flush();
}
}
else if (string.IsNullOrEmpty(httpMethod))
{
wreq.Method = "GET";
}
else
{
wreq.Method = httpMethod;
}
try
{
wrsp = wreq.GetResponse() as HttpWebResponse;
if (wrsp.StatusCode != HttpStatusCode.NoContent)
{
using (var reader = JsonTextReader.CreateFrom(new StreamReader(wrsp.GetResponseStream())))
{
object data = null;
try
{
data = reader.ParseSubtree();
}
catch (ExpectingException eex)
{
var ex = new JsonObject();
ex.Add("status_code", -39);
ex.Add("status_message", "Malformed or empty JSON data returned: " + eex.Message);
ex.Add("http_status", (int)wrsp.StatusCode);
ex.Add("http_status_message", wrsp.StatusDescription);
throw new JsonRpcException(ex);
}
if (null != fixupResponse)
{
data = fixupResponse(data);
}
if (!string.IsNullOrEmpty(timestampField))
{
var d = data as IDictionary <string, object>;
if (null != d)
{
DateTime dt = DateTime.UtcNow;
d.Add(timestampField, dt.ToString("O"));
}
}
return(data);
}
}
else
{
return(null);
}
}
catch (Exception ex)
{
var wex = ex as WebException;
if (null != wex)
{
if (null == wrsp)
{
wrsp = wex.Response as HttpWebResponse;
}
if (null != wrsp)
{
using (var reader = JsonTextReader.CreateFrom(new StreamReader(wrsp.GetResponseStream())))
{
object data = null;
try
{
data = reader.ParseSubtree();
}
catch (ExpectingException eex)
{
var jex = new JsonObject();
jex.Add("status_code", -39);
jex.Add("status_message", "Malformed or empty JSON data returned: " + eex.Message);
jex.Add("http_status", (int)wrsp.StatusCode);
jex.Add("http_status_message", wrsp.StatusDescription);
data = jex;
}
if (null != fixupError)
{
data = fixupError(data);
}
var d = data as IDictionary <string, object>;
if (!string.IsNullOrEmpty(timestampField))
{
if (null != d)
{
d.Add(timestampField, DateTime.UtcNow.ToString("O"));
}
}
if (null != d)
{
throw new JsonRpcException(d);
}
}
}
}
throw;
}
}