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Posted to dev@lucene.apache.org by "Nick Veenhof (Issue Comment Edited) (JIRA)" <ji...@apache.org> on 2011/11/05 08:44:51 UTC
[jira] [Issue Comment Edited] (SOLR-2878) Regression in
SolrDispatchFilter.java concerning the getOutputStream vs getWriter
[ https://issues.apache.org/jira/browse/SOLR-2878?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13144622#comment-13144622 ]
Nick Veenhof edited comment on SOLR-2878 at 11/5/11 7:44 AM:
-------------------------------------------------------------
I'm trying to understand the conceptual change between getWriter and getOutputStream but so far I am not convinced that the problem lies with CharResponseWrapper.
1) When I change the getOutputStream to getWriter in SolrDispatchFilter and in my code, everything is working
2) When removing that flush, my headers are added.
The header added relies on the response that came back from the other filters so I need to add the header after the chain.doFilter. I did not give you a correct sample in the first post.
{code}
public void doFilter(ServletRequest req, ServletResponse res,FilterChain chain)
throws IOException, ServletException {
...
Writer out = new OutputStreamWriter(response.getOutputStream(), "UTF8"); //auto flush
out = new FastWriter(out);
// convert to a chartext
CharResponseWrapper wrapper = new CharResponseWrapper((HttpServletResponse) response);
chain.doFilter(request, wrapper);
String responseBody = wrapper.toString();
//write the outgoing header. Only succeeds when flush of solrDispatchFilter is commented out
response.addHeader("pragma", "somevalue" + responseBody + ";");
out.write(responseBody);
...
{code}
Also, the class that you found for CharResponseWrapper is the one we use. There is however another example that can be found here (but it is not solving the problem)
http://www.java2s.com/Tutorial/Java/0400__Servlet/Filterthatusesaresponsewrappertoconvertalloutputtouppercase.htm
They are using getWriter()
was (Author: nick.veenhof):
I'm trying to understand the conceptual change between getWriter and getOutputStream but so far I am not convinced that the problem lies with CharResponseWrapper.
1) When I change the getOutputStream to getWriter in SolrDispatchFilter and in my code, everything is working
2) When removing that flush, my headers are added.
The header added relies on the response that came back from the other filters so I need to add the header after the chain.doFilter. I did not give you a correct sample in the first post.
{code}
public void doFilter(ServletRequest req, ServletResponse res,FilterChain chain)
throws IOException, ServletException {
...
Writer out = new OutputStreamWriter(response.getOutputStream(), "UTF8"); //auto flush
out = new FastWriter(out);
// convert to a chartext
CharResponseWrapper wrapper = new CharResponseWrapper((HttpServletResponse) response);
chain.doFilter(request, wrapper);
String responseBody = wrapper.toString();
//write the outgoing header. Only succeeds when flush of solrDispatchFilter is commented out
response.addHeader("pragma", "somevalue" + responseBody + ";");
out.write(responseBody);
...
{code}
> Regression in SolrDispatchFilter.java concerning the getOutputStream vs getWriter
> ---------------------------------------------------------------------------------
>
> Key: SOLR-2878
> URL: https://issues.apache.org/jira/browse/SOLR-2878
> Project: Solr
> Issue Type: Bug
> Components: Build, Response Writers
> Affects Versions: 3.4
> Environment: Any unix system, it's a global problem
> Reporter: Nick Veenhof
> Labels: filter, getOutputStream, getWriter, regression
> Fix For: 3.5, 4.0
>
>
> In solr 1.4 we used getWriter in the writeResponse for solrDispatchFilter::doFilter which invoked writeResponse.
> This code looked in summary like this :
> {code:title=solrDispatchFilter.java|borderStyle=solid}
> private void writeResponse(SolrQueryResponse solrRsp, ServletResponse response,
> QueryResponseWriter responseWriter, SolrQueryRequest solrReq, Method reqMethod)
> throws IOException {
> ...
> PrintWriter out = response.getWriter();
> responseWriter.write(out, solrReq, solrRsp);
> ...
> {code}
> In solr 3.x this has changed to something like this
> {code:title=solrDispatchFilter.java|borderStyle=solid}
> private void writeResponse(SolrQueryResponse solrRsp, ServletResponse response,
> QueryResponseWriter responseWriter, SolrQueryRequest solrReq, Method reqMethod)
> throws IOException {
> ...
> String charset = ContentStreamBase.getCharsetFromContentType(ct);
> Writer out = (charset == null || charset.equalsIgnoreCase("UTF-8"))
> ? new OutputStreamWriter(response.getOutputStream(), UTF8)
> : new OutputStreamWriter(response.getOutputStream(), charset);
> out = new FastWriter(out);
> responseWriter.write(out, solrReq, solrRsp);
> out.flush();
> ...
> {code}
> Now, when we add another filter that tries to modify the output it is being blocked by the out.flush().
> flush() is telling our outputstream that it can write directly to the destination (similar to the out.close()), since this normally happens automatically there shouldn't be a need to execute this flush.
> In our case this secondary filter is trying to add headers to the response object. When we were using getwriter() it was not closing the writer so we could still modify this output. Since the flush happens now we are no longer able to modify the headers accordingly.
> It would be an easy fix if the flush could be commented out and everything would work but that is not the case. The headers are working when this happens but there is no more output.
> When I modify both classes to use getWriter() everything is working as expected.
> This is a severe regression for our use of solr.
> Our code that is used in the filter
> {code:title=solrCustomFilter.java|borderStyle=solid}
> public void doFilter(ServletRequest req, ServletResponse res,FilterChain chain)
> throws IOException, ServletException {
> ...
> Writer out = new OutputStreamWriter(response.getOutputStream(), "UTF8"); //auto flush
> out = new FastWriter(out);
> // convert to a chartext
> CharResponseWrapper wrapper = new CharResponseWrapper((HttpServletResponse) response);
> chain.doFilter(request, wrapper);
> String responseBody = wrapper.toString();
> //write the outgoing header. Only succeeds when flush of solrDispatchFilter is commented out
> response.addHeader("pragma", "somevalue;");
> out.write(responseBody);
> ...
> {code}
> Sources :
> {quote}
> SRV.5.5 Closure of Response Object
> When a response is closed, the container must immediately flush all remaining content in the response buffer to the client. The following events indicate that the servlet has satisfied the request and that the response object is to be closed:
> • The termination of the service method of the servlet.
> • The amount of content specified in the setContentLength method of the response has been written to the response.
> • The sendError method is called.
> • The sendRedirect method is called.
> {quote}
> Solr 1.4 https://svn.apache.org/repos/asf/lucene/solr/branches/branch-1.4/src/webapp/src/org/apache/solr/servlet/SolrDispatchFilter.java
> Solr 3.4 https://svn.apache.org/repos/asf/lucene/dev/branches/lucene_solr_3_4/solr/core/src/java/org/apache/solr/servlet/SolrDispatchFilter.java
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