Content-Length header already present

Question

I am using the Apache HttpClient (4.1) included in Android to execute a HttpPut. I have verified that I only have 1 content-length header. However, every time I send the request, I get a protocol exception about the Content-Length header already specified.

HttpClient client = new DefaultHttpClient();
putMethod = new HttpPut(url + encodedFileName);
putMethod.addHeader(..)  //<-once for each header
putMethod.setEntity(new ByteArrayEntity(data));
client.execute(putMethod);  //throws Exception

Caused by: org.apache.http.ProtocolException: Content-Length header already present at org.apache.http.protocol.RequestContent.process(RequestContent.java:70) at org.apache.http.protocol.BasicHttpProcessor.process(BasicHttpProcessor.java:290)

Any ideas?

Answer 1

As pointed out by igor.zh, this problem can occur if using Spring's HttpComponentsMessageSender class. To be more precise though, this is only a problem if you are passing your own instance of HttpClient into the HttpComponentsMessageSender constructor - the issue is handled automatically otherwise.

As of spring-ws 2.1.4, the HttpComponentsMessageSender.RemoveSoapHeadersInterceptor subclass that is used in the default constructor was made public to address this issue (see https://jira.spring.io/browse/SWS-835) and so can be used in your own HttpClient instances instead of writing your own class to do it. It also clears the HTTP.TRANSFER_ENCODING header.

Use the HttpClientBuilder.addInterceptorFirst method to inject this interceptor into your own HttpClient instance. Example below using XML bean wiring. If anybody knows a more concise way of constructing the HttpClient instance (aside from writing a factory bean class), I'm all ears!

<bean id="httpClientBuilder" class="org.apache.http.impl.client.HttpClientBuilder" factory-method="create"/>

<bean id="interceptedHttpClientBuilder" class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
    <property name="targetObject" ref="httpClientBuilder" />
    <property name="targetMethod" value="addInterceptorFirst"> </property>
    <property name="arguments">
        <list>
            <bean class="org.springframework.ws.transport.http.HttpComponentsMessageSender.RemoveSoapHeadersInterceptor"/>
        </list>
    </property>
</bean>

<bean id="httpClient" factory-bean="interceptedHttpClientBuilder" factory-method="build" />

<bean id="webServiceTemplate" class="org.springframework.ws.client.core.WebServiceTemplate">
    <constructor-arg ref="messageFactory"/>
    <property name="messageSender">
        <bean class="org.springframework.ws.transport.http.HttpComponentsMessageSender">
            <property name="httpClient" ref="httpClient"/>
        </bean>
    </property>
</bean>

Alternatively, if you can, just allow HttpComponentsMessageSender to construct its own HttpClient instance rather than passing one to it. Minor note on this: as of spring-ws 2.2.0-RELEASE, the default constructor for HttpComponentsMessageSender continues to use the DefaultHttpClient class, which is now deprecated. Hopefully this will be addressed in a future release.

Answer 2

That happens to me when I used http://docs.spring.io/spring-ws/site/apidocs/org/springframework/ws/transport/http/HttpComponentsMessageSender.html as a Spring WebService Message Sender. In that case the stuff like HttpPut or HttpRequest are not easily accessible, so, building HttpClient with HttpClientBuilder, I ended up inserting a HttpRequestInterceptor in front of the culprit RequestContent :

private static class ContentLengthHeaderRemover implements HttpRequestInterceptor{
    @Override
    public void process(HttpRequest request, HttpContext context) throws HttpException, IOException {
        request.removeHeaders(HTTP.CONTENT_LEN);// fighting org.apache.http.protocol.RequestContent's ProtocolException("Content-Length header already present");
    }
}
...
    HttpClientBuilder httpClientBuilder = HttpClients.custom();
    httpClientBuilder.addInterceptorFirst(new CcontentLengthHeaderRemover());

Answer 3

I've not used HttpClient myself, but I suspect that the problem is that putMethod.setEntity(...) is implicitly supplying a content length and you are also setting it explicitly via one of the putMethod.addHeader(...) calls.