WSO2 ESB: Unexpected Character Error when submitting JSON to Proxy Service

Question

I'm attempting to retrieve data from Facebook using the WSO2 Facebook Connector in WSO2 ESB 4.9.0. I've provided the proxy configuration below.

<?xml version="1.0" encoding="UTF-8"?>
<proxy xmlns="http://ws.apache.org/ns/synapse"
       name="facebook_getFeed"
       transports="https,http"
       statistics="disable"
       trace="disable"
       startOnLoad="true">
   <target>
      <inSequence onError="fault">
         <property name="messageType" value="application/json" scope="axis2"/>
         <log level="full"/>
         <property name="apiUrl" expression="json-eval($.apiUrl)"/>
         <property name="apiVersion" expression="json-eval($.apiVersion)"/>
         <property name="accessToken" expression="json-eval($.accessToken)"/>
         <property name="userId" expression="json-eval($.userId)"/>
         <property name="numOfFeeds" expression="json-eval($.numOfFeeds)"/>
         <property name="fields" expression="json-eval($.fields)"/>
         <facebook.init>
            <apiUrl>{$ctx:apiUrl}</apiUrl>
            <accessToken>{$ctx:accessToken}</accessToken>
            <apiVersion>{$ctx:apiVersion}</apiVersion>
         </facebook.init>
         <facebook.getFeeds>
            <userId>{$ctx:userId}</userId>
            <numOfFeeds>{$ctx:numOfFeeds}</numOfFeeds>
            <fields>{$ctx:fields}</fields>
         </facebook.getFeeds>
         <respond/>
      </inSequence>
      <outSequence>
         <property name="messageType" value="application/json" scope="axis2"/>
         <send/>
      </outSequence>
   </target>
   <description/>
</proxy>

The issue I'm having is that whenever I make a POST request to the service it times out. Checking the ESB error logs it appears that there was an "Error While building Passthrough stream".

[2015-12-15 15:16:54,284] ERROR - RelayUtils Error while building Passthrough stream
org.apache.axiom.om.OMException: com.ctc.wstx.exc.WstxUnexpectedCharException: Unexpected character '{' (code 123) in prolog; expected '<'
 at [row,col {unknown-source}]: [1,1]
        at org.apache.axiom.om.impl.builder.StAXOMBuilder.next(StAXOMBuilder.java:296)
        at org.apache.axiom.om.impl.llom.OMDocumentImpl.getOMDocumentElement(OMDocumentImpl.java:109)
        at org.apache.axiom.om.impl.builder.StAXOMBuilder.getDocumentElement(StAXOMBuilder.java:570)
        at org.apache.axiom.om.impl.builder.StAXOMBuilder.getDocumentElement(StAXOMBuilder.java:566)
        at org.apache.synapse.transport.passthru.util.DeferredMessageBuilder.getDocument(DeferredMessageBuilder.java:149)
        at org.apache.synapse.transport.passthru.util.RelayUtils.builldMessage(RelayUtils.java:133)
        at org.apache.synapse.transport.passthru.util.RelayUtils.buildMessage(RelayUtils.java:98)
        at org.apache.synapse.mediators.AbstractListMediator.mediate(AbstractListMediator.java:72)
        at org.apache.synapse.mediators.AbstractListMediator.mediate(AbstractListMediator.java:48)
        at org.apache.synapse.mediators.base.SequenceMediator.mediate(SequenceMediator.java:149)
        at org.apache.synapse.core.axis2.ProxyServiceMessageReceiver.receive(ProxyServiceMessageReceiver.java:185)
        at org.apache.axis2.engine.AxisEngine.receive(AxisEngine.java:180)
        at org.apache.synapse.transport.passthru.ServerWorker.processNonEntityEnclosingRESTHandler(ServerWorker.java:317)
        at org.apache.synapse.transport.passthru.ServerWorker.processEntityEnclosingRequest(ServerWorker.java:363)
        at org.apache.synapse.transport.passthru.ServerWorker.run(ServerWorker.java:142)
        at org.apache.axis2.transport.base.threads.NativeWorkerPool$1.run(NativeWorkerPool.java:172)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:745)
Caused by: com.ctc.wstx.exc.WstxUnexpectedCharException: Unexpected character '{' (code 123) in prolog; expected '<'
 at [row,col {unknown-source}]: [1,1]
        at com.ctc.wstx.sr.StreamScanner.throwUnexpectedChar(StreamScanner.java:639)
        at com.ctc.wstx.sr.BasicStreamReader.nextFromProlog(BasicStreamReader.java:2052)
        at com.ctc.wstx.sr.BasicStreamReader.next(BasicStreamReader.java:1134)
        at org.apache.axiom.util.stax.wrapper.XMLStreamReaderWrapper.next(XMLStreamReaderWrapper.java:225)
        at org.apache.axiom.util.stax.dialect.DisallowDoctypeDeclStreamReaderWrapper.next(DisallowDoctypeDeclStreamReaderWrapper.java:34)
        at org.apache.axiom.om.impl.builder.StAXOMBuilder.parserNext(StAXOMBuilder.java:681)
        at org.apache.axiom.om.impl.builder.StAXOMBuilder.next(StAXOMBuilder.java:214)
        ... 18 more
[2015-12-15 15:16:54,377] ERROR - SequenceMediator Error while building message
org.apache.axis2.AxisFault: Error while building Passthrough stream
        at org.apache.synapse.transport.passthru.util.RelayUtils.handleException(RelayUtils.java:283)
        at org.apache.synapse.transport.passthru.util.RelayUtils.builldMessage(RelayUtils.java:142)
        at org.apache.synapse.transport.passthru.util.RelayUtils.buildMessage(RelayUtils.java:98)
        at org.apache.synapse.mediators.AbstractListMediator.mediate(AbstractListMediator.java:72)
        at org.apache.synapse.mediators.AbstractListMediator.mediate(AbstractListMediator.java:48)
        at org.apache.synapse.mediators.base.SequenceMediator.mediate(SequenceMediator.java:149)
        at org.apache.synapse.core.axis2.ProxyServiceMessageReceiver.receive(ProxyServiceMessageReceiver.java:185)
        at org.apache.axis2.engine.AxisEngine.receive(AxisEngine.java:180)
        at org.apache.synapse.transport.passthru.ServerWorker.processNonEntityEnclosingRESTHandler(ServerWorker.java:317)
        at org.apache.synapse.transport.passthru.ServerWorker.processEntityEnclosingRequest(ServerWorker.java:363)
        at org.apache.synapse.transport.passthru.ServerWorker.run(ServerWorker.java:142)
        at org.apache.axis2.transport.base.threads.NativeWorkerPool$1.run(NativeWorkerPool.java:172)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:745)
Caused by: org.apache.axiom.om.OMException: com.ctc.wstx.exc.WstxUnexpectedCharException: Unexpected character '{' (code 123) in prolog; expected '<'
 at [row,col {unknown-source}]: [1,1]
        at org.apache.axiom.om.impl.builder.StAXOMBuilder.next(StAXOMBuilder.java:296)
        at org.apache.axiom.om.impl.llom.OMDocumentImpl.getOMDocumentElement(OMDocumentImpl.java:109)
        at org.apache.axiom.om.impl.builder.StAXOMBuilder.getDocumentElement(StAXOMBuilder.java:570)
        at org.apache.axiom.om.impl.builder.StAXOMBuilder.getDocumentElement(StAXOMBuilder.java:566)
        at org.apache.synapse.transport.passthru.util.DeferredMessageBuilder.getDocument(DeferredMessageBuilder.java:149)
        at org.apache.synapse.transport.passthru.util.RelayUtils.builldMessage(RelayUtils.java:133)
        ... 13 more

Referring to the proxy configuration above, I've got a log mediator which actually successfully prints the JSON payload, so that would lead me to think it has something to do with the messager formatter?

My message formatter/builder configuration within the Axis2.xml file is as follows:

<!--JSON Message Formatters-->
<messageFormatter contentType="application/json" class="org.apache.synapse.commons.json.JsonStreamFormatter"/>

<!--JSON Message Builders-->
<messageBuilder contentType="application/json" class="org.apache.synapse.commons.json.JsonStreamBuilder"/>

Everything else in this file is as per the default configuration.

What could be going wrong here?

Sample Request

Using Soap UI (Obscured IP and access token in payload):

POST http://[SERVER_IP]:8280/services/facebook_getFeed <br>
HTTP/1.1 <br>
Accept-Encoding: gzip,deflate <br>
Content-Type: application/json <br>
Content-Length: 207 <br>
Host: [SERVER_IP]:8280 <br>
Connection: Keep-Alive <br>
User-Agent: Apache-HttpClient/4.1.1 (java 1.5) <br>

Payload Data:

{
"apiUrl":"https://graph.facebook.com",
"apiVersion":"v2.4",
"accessToken":"[TOKEN HERE]",
"userId":"409521282507981",
"numOfFeeds":"10",
"fields":"message,id,created_time"
}

Wire Logs

As requested by @RavindraRanwala :

[2015-12-15 17:29:38,650] DEBUG - wire >> "POST /services/facebook_getFeed HTTP/1.1[\r][\n]"
[2015-12-15 17:29:38,652] DEBUG - wire >> "Accept-Encoding: gzip,deflate[\r][\n]"
[2015-12-15 17:29:38,653] DEBUG - wire >> "Content-Type: application/json[\r][\n]"
[2015-12-15 17:29:38,653] DEBUG - wire >> "Content-Length: 207[\r][\n]"
[2015-12-15 17:29:38,663] DEBUG - wire >> "Host: [SERVER_IP]:8280[\r][\n]"
[2015-12-15 17:29:38,663] DEBUG - wire >> "Connection: Keep-Alive[\r][\n]"
[2015-12-15 17:29:38,664] DEBUG - wire >> "User-Agent: Apache-HttpClient/4.1.1 (java 1.5)[\r][\n]"
[2015-12-15 17:29:38,665] DEBUG - wire >> "[\r][\n]"
[2015-12-15 17:29:38,666] DEBUG - wire >> "{[\n]"
[2015-12-15 17:29:38,666] DEBUG - wire >> ""apiUrl":"https://graph.facebook.com",[\n]"
[2015-12-15 17:29:38,667] DEBUG - wire >> ""apiVersion":"v2.4",[\n]"
[2015-12-15 17:29:38,668] DEBUG - wire >> ""accessToken":"[ACCESS_TOKEN]",[\n]"
[2015-12-15 17:29:38,669] DEBUG - wire >> ""userId":"409521282507981",[\n]"
[2015-12-15 17:29:38,669] DEBUG - wire >> ""numOfFeeds":"10",[\n]"
[2015-12-15 17:29:38,679] DEBUG - wire >> ""fields":"message,id,created_time"[\n]"
[2015-12-15 17:29:38,679] DEBUG - wire >> "}"
[2015-12-15 17:29:38,812]  INFO - LogMediator To: /services/facebook_getFeed, MessageID: urn:uuid:27814841-6067-466c-b55f-b7fdd67c8d3b, Direction: request, Payload: {
"apiUrl":"https://graph.facebook.com",
"apiVersion":"v2.4",
"accessToken":"[ACCESS_TOKEN]",
"userId":"409521282507981",
"numOfFeeds":"10",
"fields":"message,id,created_time"
}
[2015-12-15 17:29:38,909]  INFO - TimeoutHandler This engine will expire all callbacks after : 120 seconds, irrespective of the timeout action, after the specified or optional timeout
[2015-12-15 17:29:40,267] DEBUG - wire << "GET /409521282507981/feed?limit=10&access_token=[ACCESS_TOKEN]&fields= HTTP/1.1[\r][\n]"
[2015-12-15 17:29:40,269] DEBUG - wire << "Accept-Encoding: gzip,deflate[\r][\n]"
[2015-12-15 17:29:40,278] DEBUG - wire << "Content-Type: application/json[\r][\n]"
[2015-12-15 17:29:40,279] DEBUG - wire << "Host: graph.facebook.com:443[\r][\n]"
[2015-12-15 17:29:40,280] DEBUG - wire << "Connection: Keep-Alive[\r][\n]"
[2015-12-15 17:29:40,281] DEBUG - wire << "User-Agent: Synapse-PT-HttpComponents-NIO[\r][\n]"
[2015-12-15 17:29:40,281] DEBUG - wire << "[\r][\n]"
[2015-12-15 17:29:40,554] DEBUG - wire >> "HTTP/1.1 200 OK[\r][\n]"
[2015-12-15 17:29:40,557] DEBUG - wire >> "Access-Control-Allow-Origin: *[\r][\n]"
[2015-12-15 17:29:40,558] DEBUG - wire >> "Content-Type: text/javascript; charset=UTF-8[\r][\n]"
[2015-12-15 17:29:40,559] DEBUG - wire >> "X-FB-Trace-ID: E5Iewv3ixeR[\r][\n]"
[2015-12-15 17:29:40,560] DEBUG - wire >> "X-FB-Rev: 2091546[\r][\n]"
[2015-12-15 17:29:40,561] DEBUG - wire >> "ETag: "ca13846784e4a3383090ca79b7a295fd23aa5641"[\r][\n]"
[2015-12-15 17:29:40,561] DEBUG - wire >> "Pragma: no-cache[\r][\n]"
[2015-12-15 17:29:40,562] DEBUG - wire >> "Cache-Control: private, no-cache, no-store, must-revalidate[\r][\n]"
[2015-12-15 17:29:40,563] DEBUG - wire >> "Facebook-API-Version: v2.5[\r][\n]"
[2015-12-15 17:29:40,563] DEBUG - wire >> "Expires: Sat, 01 Jan 2000 00:00:00 GMT[\r][\n]"
[2015-12-15 17:29:40,564] DEBUG - wire >> "Vary: Accept-Encoding[\r][\n]"
[2015-12-15 17:29:40,565] DEBUG - wire >> "Content-Encoding: gzip[\r][\n]"
[2015-12-15 17:29:40,565] DEBUG - wire >> "X-FB-Debug: G+b1bsKrSFxPDc4u1RDGIpHACsTbiJV6n1nGgNfMYwc0IqGO2fif1pnr9/o/dhQ1DLSpl7pXheknjzMwvH948w==[\r][\n]"
[2015-12-15 17:29:40,575] DEBUG - wire >> "Date: Tue, 15 Dec 2015 06:29:46 GMT[\r][\n]"
[2015-12-15 17:29:40,576] DEBUG - wire >> "Connection: keep-alive[\r][\n]"
[2015-12-15 17:29:40,578] DEBUG - wire >> "Content-Length: 814[\r][\n]"
[2015-12-15 17:29:40,579] DEBUG - wire >> "[\r][\n]"
[2015-12-15 17:29:40,580] DEBUG - wire >> "[0x1f][0x8b][0x8][0x0][0x0][0x0][0x0][0x0][0x0][0x3][0xad][0x93][0xef]o[0xa3]6[0x18][0xc7][0xff][0x15][0xc4][0x8b]J[0xd3]z[0x89]⌂[0x3][0x96][0xaa][0x89]$M[0xbb][0xb4][0xd7]6[0x97]\[0xda][0xb0]L[0x91]K[0x1c]B![0x98][0x82][0x9][0xcd]z[0xfd][0xdf]g[0xba]{Q[0xe5][0xa6]p[0x9a][0x6][0xbc][0xb0][0x85][0xad][0xcf][0xd7][0x1f]?[0xcf][0xab][0xbd][0x12]Z[0xd8][0xfc][0x8f]W{+[0xcb]RD[0xd2][0xe6][0xf6
3][0x97][0x96][0xf9][0x84]u[0xa5]D*,[0xfe][0x8b]}j[0x87][0x85][0x14]Z[0xae][0x96]:[0xde]6k[0x10][0x80][0xf8][0x13][0x84][0x9f][0x90];[0x5][0x88][0x3][0xc8][0xb1][0xfb]+0[0x8f]Y[0x19][0xaf][0xcc]⌂[0x2]<[0x8a] r[0x11][0x5][0x8e][0xe7][0xc2]%[0xc4].t[0x10]c[0x18][0x1][0x87]B[0x97][0xd8]o[0xa7][0x1f][0x91][0x13][0xb5][0x95]z[0x13]gQ[0xc3][0xad][0xb]e[0x6][0x1b]Y[0xc8][0xce]q0[0xe0][0x80]q[0xe0][0x1d][0x5][0x13][0x88] c[0x84][0xb9][0x1
][0x10]y[0x7][0xdc]QUjK[0xcb]R7[0xe8]T[0x85]B[0xc7]*[0xb3]D$[0xe2][0xac][0xd3]9Fw[0xa6][0x8]sJ8[0xa6][0xed]t[0xc]IC'[0xc][0x1e][0xd0][0xef][\n]"
[2015-12-15 17:29:40,592] DEBUG - wire >> "[0xa9][0xf5][0xde]*k)[0xb5][0x95][0xa7]"[0x94][0x96]V[0xd6]F[0xec][0xa4][0x95]VY[0xb8]i[\r][0x80][0x10][0x87][0xc7][0xbd]7[0x1](1/u[0xcc][0xdc]=[0x8][0xf0][0xbb]U[0x8b][0xd2]j[0xc4]'[0x8d][0x0][0xf1][0xa8]*[0xdd]L[0xcb][0xf].B][0x89]4[0xdd][0xb7]E[0x81][0x88]#[0xa7]5[\n]"
[2015-12-15 17:29:40,595] DEBUG - wire >> "![0xd8]3Q<[0x0][0xf0]A[0x94][0xdb][0x8d]%[0xb2][0x95][0xb5][0x15][0xfb]Gy[0x18][0xc1][0x94][0x84]L[0xd3][0x9f][0xb8][0x10]@9[0x81][0xad]!0[0x81][0xc]![0xc2][0x98]w[0x18][0xc2]7[0x9][0xc2][0x8d][0xc][0x13][0xeb][0x7][0x11][0xc7][0xd1][0x88]c[0xc2]I{-[0x98]6[0xf0]L-P[0xec][0xb2][0x1f][0xce]⌂[0xfa].@[0xa4][0xa5]2[0x3][0xa5]M[0xfd][[0xb9]2[0xe5][0xb9].[0xd4][0xd6]d[0x91]VU[0xca][0xa2]E[0x81][
0x4][0x8f][0xa3]v[0x5]f[\n]"
[2015-12-15 17:29:40,596] DEBUG - wire >> ")uMq[0x1e][0xd6][0xa4][0xff][0x1]*[0xde][0x91]mD[0xe0]p[0xc4]Z[0x89][0xc0][0x81][0xa0]!:[0x18][0x1d][0x12][0x9b]S[0xff]T[0xc7]AN[0xcd][0xd7][0xde][0xef][0x0]3dX[0x18][0xb8][0xc0]~[0xfb][0xf3][0xd4][0xce]Ed[0xca][0xdb][0xe6][0xaf]v^[0xc8]][0xac][0xaa][0xd2]l[0xdc]h[0x9d][0x97]|[0xd1]]t[0xa3]B[0xe4][0x9b][0xce][0xda][0xb4][0xdf][0xa3]RI'T[n[0xea]t[0xd1][0xdd][0xa1][0xe]]t[0xf][0x0][0x8b][0x
xca][0xd5]oi[0xbc][0x8d][0xf5][0x19][0x4]'e[0x9c][0x85][0xf2][0xcc][0xdc]+e[0xc0],uOD[0x18][0x9a][0xa3]-[0xb5]Jdv[0x6][0x1d][0xe8]0[0x8][0x8c]l[0x88][0x18]`[0xee][0xb7]Y[0xaa][0xcb][0xde]6z[0xca][0xa6][0x18][0xe6]j[0xb6][0xbf][0xf4][0x96]U[0x8][0x7][0xe]B[0xf5][0xc9]r[0xf9]O[0xd0][0xef]{e[0x16].[0xfd][0x95]?N@[0x8][0x8a]z[0x94][0x8c][0xb0]?q[0x82][0xde][0xa4][0x1e]^[0x87][0xec]9[0xae]f~[0x92]D[0x14][0xf5]\[0x15][0xf4][0xcb]"[0xbc]
]d=[0xbc]x[0x92][0xee]\&[0xdb][0xfb]r[0xf0][0xbc]&[0x81]/[0xf4]|[0x15][0x5][0xfe][0xe7]/[0x8f][0xf1][0x1d]<⌂[0xa9][0xf7]+_EW[0x15]c[0x13]W[0xcb]$y[0xbe][0x9a]{[0xeb][0x9b][0x88][0xc2]r[0x1a][0xf4][0xf2][0xcf][0xf7][0xa3]][0x1d][0xc][0x82]A[0x13][0xe5][0xbb][0xa9]3hLg[0xf2]E[0xff]⌂[0xca][0xfe][0xbb][0xa1]*[0xd3]q[0xfa].[0x9b][0x9a].[0x82][0xde][0xbf]+[0x1b][0xf4][0xc7][0xf2][0xe6]|>[0xc3]t|[[0x8f]]q3[0x8c][0xf1][0xae][0x9f][0x93][0
xe8]k[0x8c]/[0xef][0xee]f[0xe7][0xc9][0xa4][0xbe][0x8c][0x3]?[0xbd][0xdf][0xe5]_[0xfb]/[0xfb][0xb1][0x1f][0xf4][0xc9]5[0xb9][0x9e][0x5]f0[0xdd][0x8f]Y[0xe0][0xc3][0xc9][0xee]<{[0xc8].[0xd4]z>[0xa4]^[0xc8]*⌂=[0x99][0xc6][0xf][0x4][0xdc]#:q[0x9d][0xa2][0xff][0xc4]n[0x91][0xfc][0xcb][0x1b]^[0xd4][0xf]Q[0xa3][0xcc]~{[0xfb][0x1b][0x92][0x12][0xdf])M[0x7][0x0][0x0]"
[2015-12-15 17:29:40,674] ERROR - RelayUtils Error while building Passthrough stream
org.apache.axiom.om.OMException: com.ctc.wstx.exc.WstxUnexpectedCharException: Unexpected character '{' (code 123) in prolog; expected '<'
 at [row,col {unknown-source}]: [1,1]
        at org.apache.axiom.om.impl.builder.StAXOMBuilder.next(StAXOMBuilder.java:296)
        at org.apache.axiom.om.impl.llom.OMDocumentImpl.getOMDocumentElement(OMDocumentImpl.java:109)
        at org.apache.axiom.om.impl.builder.StAXOMBuilder.getDocumentElement(StAXOMBuilder.java:570)
        at org.apache.axiom.om.impl.builder.StAXOMBuilder.getDocumentElement(StAXOMBuilder.java:566)
        at org.apache.synapse.transport.passthru.util.DeferredMessageBuilder.getDocument(DeferredMessageBuilder.java:149)
        at org.apache.synapse.transport.passthru.util.RelayUtils.builldMessage(RelayUtils.java:133)
        at org.apache.synapse.transport.passthru.util.RelayUtils.buildMessage(RelayUtils.java:98)
        at org.apache.synapse.mediators.AbstractListMediator.mediate(AbstractListMediator.java:72)
        at org.apache.synapse.mediators.template.InvokeMediator.mediate(InvokeMediator.java:154)
        at org.apache.synapse.mediators.base.SequenceMediator.mediate(SequenceMediator.java:267)
        at org.apache.synapse.core.axis2.Axis2SynapseEnvironment.mediateFromContinuationStateStack(Axis2SynapseEnvironment.java:679)
        at org.apache.synapse.core.axis2.Axis2SynapseEnvironment.injectMessage(Axis2SynapseEnvironment.java:244)
        at org.apache.synapse.core.axis2.SynapseCallbackReceiver.handleMessage(SynapseCallbackReceiver.java:529)
        at org.apache.synapse.core.axis2.SynapseCallbackReceiver.receive(SynapseCallbackReceiver.java:172)
        at org.apache.axis2.engine.AxisEngine.receive(AxisEngine.java:180)
        at org.apache.synapse.transport.passthru.ClientWorker.run(ClientWorker.java:247)
        at org.apache.axis2.transport.base.threads.NativeWorkerPool$1.run(NativeWorkerPool.java:172)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:745)
Caused by: com.ctc.wstx.exc.WstxUnexpectedCharException: Unexpected character '{' (code 123) in prolog; expected '<'
 at [row,col {unknown-source}]: [1,1]
        at com.ctc.wstx.sr.StreamScanner.throwUnexpectedChar(StreamScanner.java:639)
        at com.ctc.wstx.sr.BasicStreamReader.nextFromProlog(BasicStreamReader.java:2052)
        at com.ctc.wstx.sr.BasicStreamReader.next(BasicStreamReader.java:1134)
        at org.apache.axiom.util.stax.wrapper.XMLStreamReaderWrapper.next(XMLStreamReaderWrapper.java:225)
        at org.apache.axiom.util.stax.dialect.DisallowDoctypeDeclStreamReaderWrapper.next(DisallowDoctypeDeclStreamReaderWrapper.java:34)
        at org.apache.axiom.om.impl.builder.StAXOMBuilder.parserNext(StAXOMBuilder.java:681)
        at org.apache.axiom.om.impl.builder.StAXOMBuilder.next(StAXOMBuilder.java:214)
        ... 19 more
[2015-12-15 17:29:40,902] ERROR - TemplateMediator Error while building message
org.apache.axis2.AxisFault: Error while building Passthrough stream
        at org.apache.synapse.transport.passthru.util.RelayUtils.handleException(RelayUtils.java:283)
        at org.apache.synapse.transport.passthru.util.RelayUtils.builldMessage(RelayUtils.java:142)
        at org.apache.synapse.transport.passthru.util.RelayUtils.buildMessage(RelayUtils.java:98)
        at org.apache.synapse.mediators.AbstractListMediator.mediate(AbstractListMediator.java:72)
        at org.apache.synapse.mediators.template.InvokeMediator.mediate(InvokeMediator.java:154)
        at org.apache.synapse.mediators.base.SequenceMediator.mediate(SequenceMediator.java:267)
        at org.apache.synapse.core.axis2.Axis2SynapseEnvironment.mediateFromContinuationStateStack(Axis2SynapseEnvironment.java:679)
        at org.apache.synapse.core.axis2.Axis2SynapseEnvironment.injectMessage(Axis2SynapseEnvironment.java:244)
        at org.apache.synapse.core.axis2.SynapseCallbackReceiver.handleMessage(SynapseCallbackReceiver.java:529)
        at org.apache.synapse.core.axis2.SynapseCallbackReceiver.receive(SynapseCallbackReceiver.java:172)
        at org.apache.axis2.engine.AxisEngine.receive(AxisEngine.java:180)
        at org.apache.synapse.transport.passthru.ClientWorker.run(ClientWorker.java:247)
        at org.apache.axis2.transport.base.threads.NativeWorkerPool$1.run(NativeWorkerPool.java:172)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:745)
Caused by: org.apache.axiom.om.OMException: com.ctc.wstx.exc.WstxUnexpectedCharException: Unexpected character '{' (code 123) in prolog; expected '<'
 at [row,col {unknown-source}]: [1,1]
        at org.apache.axiom.om.impl.builder.StAXOMBuilder.next(StAXOMBuilder.java:296)
        at org.apache.axiom.om.impl.llom.OMDocumentImpl.getOMDocumentElement(OMDocumentImpl.java:109)
        at org.apache.axiom.om.impl.builder.StAXOMBuilder.getDocumentElement(StAXOMBuilder.java:570)
        at org.apache.axiom.om.impl.builder.StAXOMBuilder.getDocumentElement(StAXOMBuilder.java:566)
        at org.apache.synapse.transport.passthru.util.DeferredMessageBuilder.getDocument(DeferredMessageBuilder.java:149)
        at org.apache.synapse.transport.passthru.util.RelayUtils.builldMessage(RelayUtils.java:133)
        ... 14 more
Caused by: com.ctc.wstx.exc.WstxUnexpectedCharException: Unexpected character '{' (code 123) in prolog; expected '<'
 at [row,col {unknown-source}]: [1,1]
        at com.ctc.wstx.sr.StreamScanner.throwUnexpectedChar(StreamScanner.java:639)
        at com.ctc.wstx.sr.BasicStreamReader.nextFromProlog(BasicStreamReader.java:2052)
        at com.ctc.wstx.sr.BasicStreamReader.next(BasicStreamReader.java:1134)
        at org.apache.axiom.util.stax.wrapper.XMLStreamReaderWrapper.next(XMLStreamReaderWrapper.java:225)
        at org.apache.axiom.util.stax.dialect.DisallowDoctypeDeclStreamReaderWrapper.next(DisallowDoctypeDeclStreamReaderWrapper.java:34)
        at org.apache.axiom.om.impl.builder.StAXOMBuilder.parserNext(StAXOMBuilder.java:681)
        at org.apache.axiom.om.impl.builder.StAXOMBuilder.next(StAXOMBuilder.java:214)
        ... 19 more
[2015-12-15 17:29:40,991] ERROR - LogMediator To: http://www.w3.org/2005/08/addressing/anonymous, WSAction: , SOAPAction: , MessageID: urn:uuid:85e6d771-e7c6-4764-8431-01e0fb4782e6, Direction: request, MESSAGE = Executing default 'fault' sequence, ERROR_CODE = 0, ERROR_MESSAGE = Error while building message, Envelope: <?xml version='1.0' encoding='utf-8'?><soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
nv:Body/></soapenv:Envelope>

can you share the sample request that you send to the proxy? I didn't try getFeed yet. But I have tried quite few fb operations via the connector. alokayasoya.blogspot.com/2015/12/how-to-use-facebook-connector-with-wso2.html — Thusitha Thilina Dayaratne, Dec 15 '15 at 05:10
@ThusithaThilinaDayaratne please see the revised question for a sample request :) I'm reading through the article you referred to now. Thanks for your help. — Strainy, Dec 15 '15 at 05:17
could you try without fields and check if you you able to get back the response successfulkly — Thusitha Thilina Dayaratne, Dec 15 '15 at 05:31
Can you please enable wire logs as follows and share it with us.Move into $ESB_HOME/repository/logs and locate log4j.properties file. Then un comment following line: log4j.logger.org.apache.synapse.transport.http.wire=DEBUG — Ravindra Ranwala, Dec 15 '15 at 05:41
@ThusithaThilinaDayaratne I've enabled the MessageFormatter and MessageBuilder as per your article. I've also removed the fields component of the request to no avail. — Strainy, Dec 15 '15 at 06:26
@RavindraRanwala thank you for taking the time to comment. I'll try to retrieve the wire logs now. — Strainy, Dec 15 '15 at 06:26
@RavindraRanwala please see the revised question for the wire logs :) — Strainy, Dec 15 '15 at 06:37
I analysed the wire log and it seems that the ESB does not send the payload to the backend API. Also I found that we have upgraded this connector API recently. Are you using the latest connector version? If not please go ahead and download the latest version from the connector store. The connector was upgraded due to the API changes. — Ravindra Ranwala, Dec 15 '15 at 07:07
@RavindraRanwala is this the Facebook connector or the actual connector api? The WSO2 store says the version for the facebook connector is 1.0.0, which is what is was when I downloaded it. I'm not sure how to go about upgrading the connector module itself. — Strainy, Dec 15 '15 at 07:17
Actually, looking at those wire logs it looks like Facebook is returning data with the content-type "text/javascript", I don't have a message builder/formatter for that, could that be the issue? — Strainy, Dec 15 '15 at 07:20
Though the connector was upgraded, still the same version was kept. It was upgraded around 3 months back I guess. Just download the current connector from the store and try it out again. — Ravindra Ranwala, Dec 15 '15 at 07:20
It works now. Thanks for the tip RE the wire logs @RavindraRanwala that turns out I needed a message formatter/builder for text/javascript response from the Facebook. This isn't detailed in the documentation! Feel free to post an answer if you want some points :) — Strainy, Dec 15 '15 at 07:30

score 6 · Accepted Answer · answered Dec 16 '15 at 02:01

Many thanks @RavindraRanwala and @ThusithaThilinaDayaratne for leading me to the resolution of this issue.

After consulting the wire logs, it appears the Facebook API is responding with text/javascript content type. I had no message builder/formatter enabled within the ESB to handle this content type, so the process ended up failing. All I needed to do was open up my axis2.xml configuration file and append the following message builders:

<!--JSON Message Builders-->
<messageBuilder contentType="application/json" class="org.apache.synapse.commons.json.JsonStreamBuilder"/>
<messageBuilder contentType="text/javascript" class="org.apache.synapse.commons.json.JsonStreamBuilder"/>

... and formatters:

<!--JSON Message Formatters-->
<messageFormatter contentType="application/json" class="org.apache.synapse.commons.json.JsonStreamFormatter"/>
<messageFormatter contentType="text/javascript" class="org.apache.synapse.commons.json.JsonStreamFormatter"/>

The most up to date documentation on the Facebook connector seems to be at the GitHub page, where all the necessary builder/formatter information is clarified:

https://github.com/wso2/esb-connectors/tree/master/facebook/facebook-connector/facebook-connector-1.0.0

I had a similar issue, I was expecting a application/json from a rest service, but I was receiveing a "application/octetstream" content type back from the server. So, the message builder wasn't able to handle the response correctly. Many thanks to you @Strainy, your solution guided me to solve my issue. — Volceri, Mar 24 '17 at 17:12

WSO2 ESB: Unexpected Character Error when submitting JSON to Proxy Service

Sample Request

Wire Logs

1 Answers1

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