Use GZIP, JSON responses and JQuery
Solution 1
If I see the response with Firebug it is empty.
There's your clue - it's not a JQuery problem, it's server-side. (I'm afraid I can't help you with that, other than to suggest you stop looking at the client-side)
There's no problem gzipping ajax responses - if you can't see the response in Firebug, then JQuery can't see it either.
Solution 2
you have to add one more header "content-encoding: gzip" if you are compressing it.
Sergio del Amo
Updated on July 20, 2022Comments
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Sergio del Amo almost 2 years
However, I want to compress my responses with GZIP wheren possible. I tried using the Compression filter code available for free download in the headfirst site. It works great for html, images, css and javascript.
I post the filter next. It checks if GZIP is an accepted encoding and it adds gzip as Content-Encoding. See:
wrappedResp.setHeader("Content-Encoding", "gzip");
public class CompressionFilter implements Filter { private ServletContext ctx; private FilterConfig cfg; /** * The init method saves the config object and a quick reference to the * servlet context object (for logging purposes). */ public void init(FilterConfig cfg) throws ServletException { this.cfg = cfg; ctx = cfg.getServletContext(); //ctx.log(cfg.getFilterName() + " initialized."); } /** * The heart of this filter wraps the response object with a Decorator * that wraps the output stream with a compression I/O stream. * Compression of the output stream is only performed if and only if * the client includes an Accept-Encoding header (specifically, for gzip). */ public void doFilter(ServletRequest req, ServletResponse resp, FilterChain fc) throws IOException, ServletException { HttpServletRequest request = (HttpServletRequest) req; HttpServletResponse response = (HttpServletResponse) resp; // Dose the client accept GZIP compression? String valid_encodings = request.getHeader("Accept-Encoding"); if ( (valid_encodings != null) && (valid_encodings.indexOf("gzip") > -1) ) { // Then wrap the response object with a compression wrapper // We'll look at this class in a minute. CompressionResponseWrapper wrappedResp = new CompressionResponseWrapper(response); // Declare that the response content is being GZIP encoded. wrappedResp.setHeader("Content-Encoding", "gzip"); // Chain to the next component (thus processing the request) fc.doFilter(request, wrappedResp); // A GZIP compression stream must be "finished" which also // flushes the GZIP stream buffer which sends all of its // data to the original response stream. GZIPOutputStream gzos = wrappedResp.getGZIPOutputStream(); gzos.finish(); // The container handles the rest of the work. //ctx.log(cfg.getFilterName() + ": finished the request."); } else { fc.doFilter(request, response); //ctx.log(cfg.getFilterName() + ": no encoding performed."); } } public void destroy() { // nulling out my instance variables cfg = null; ctx = null; } }
I was using the next code to send JSON responses in Struts web application.
public ActionForward get(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) { JSONObject json = // Do some logic here RequestUtils.populateWithJSON(response, json); return null; } public static void populateWithJSON(HttpServletResponse response,JSONObject json) { if(json!=null) { response.setContentType("text/x-json;charset=UTF-8"); response.setHeader("Cache-Control", "no-cache"); try { response.getWriter().write(json.toString()); } catch (IOException e) { throw new ApplicationException("IOException in populateWithJSON", e); } } }
It works fine without compression but if I compress JSON responses, I can not see my JSON objects anymore. I handle JSON Ajax calls with JQuery with code snippets as follows:
$.post(url,parameters, function(json) { // Do some DOM manipulation with the data contained in the JSON Object }, "json");
If I see the response with Firebug it is empty.
Should I refractor my compression filter to skip compression in JSON responses? or there is a workaround to this?
For me, it looks like JQuery does not recognize the response as JSON because I am adding the Gzip compression.
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LCJ over 9 yearsCan it be after server and before client? A problem crated by some network elements?