> Messing about with a small project: it's basically a reverse proxy
> that will convert json responses from the origin server to lovely html
> in the client request. It decodes the json response from the origin
> and passes this struct to the mustache templating engine which outputs
> html.

> The server has a config file allowing the user to specify url patterns
> to match and destination urls to proxy to:
> {
>   "pattern":"/hello",
>   "origin":"http://example.com/some/destination",
>   "template":"./hello.template"
> } // etc, etc

> I'm having difficulty understanding our friend
> httputil.NewSingleHostReverseProxy(). It may have something to do with
> the way I have approached this though.

> Ideally I have a http server. This assigns a handler for each entry in
> the config file, matched by pattern. The handler creates a new proxy
> server using httputil.NewSingleHostReverseProxy() with the origin
> config parameter as the target argument. I then have a custom
> http.RequestWriter that reads the json body in response, parses it,
> passes it to mustache and writes the output:

> ...
>        for _, route := range config.Routes {
>                url, _ := url.Parse(route.origin)
>                MustacheHandler := NewMustacheHandler(route.TemplateCache,
> url)
>                http.Handle(route.Pattern, MustacheHandler)
>        }
>        err = http.ListenAndServe(address, nil)
>        if err != nil {
>                log.Fatal("ListenAndServe: ", err)
>        }
> ...

> The mustache handler looks a little bit like this:

> func NewMustacheHandler(template []byte, url *url.URL)
> http.HandlerFunc {
>    return func(w http.ResponseWriter, r *http.Request) {
>        mw := NewMustacheWriter(w, template)
>        rw := mustacheResponseWriter{Writer: mw, ResponseWriter: w}

>        proxy := httputil.NewSingleHostReverseProxy(url)
>        proxy.ServeHTTP(rw, r)

> Are you suggesting that NewSingleHostReverseProxy is not suitable for
> this task? I may have misunderstood but I thought that this is exactly
> what NewSingleHostReverseProxy is for.

> On Apr 26, 6:50 pm, Kyle Lemons <kev...@google.com> wrote:
> > On Thu, Apr 26, 2012 at 6:58 AM, OmarShariffDontLikeIt <

> > omarshariffdontlik...@gmail.com> wrote:
> > > Hi Gophers!

> > > Messing about with a small project: it's basically a reverse proxy
> > > that will convert json responses from the origin server to lovely html
> > > in the client request. It decodes the json response from the origin
> > > and passes this struct to the mustache templating engine which outputs
> > > html.

> > > The server has a config file allowing the user to specify url patterns
> > > to match and destination urls to proxy to:
> > > {
> > >   "pattern":"/hello",
> > >   "origin":"http://example.com/some/destination",
> > >   "template":"./hello.template"
> > > } // etc, etc

> > > I'm having difficulty understanding our friend
> > > httputil.NewSingleHostReverseProxy(). It may have something to do with
> > > the way I have approached this though.

> > > Ideally I have a http server. This assigns a handler for each entry in
> > > the config file, matched by pattern. The handler creates a new proxy
> > > server using httputil.NewSingleHostReverseProxy() with the origin
> > > config parameter as the target argument. I then have a custom
> > > http.RequestWriter that reads the json body in response, parses it,
> > > passes it to mustache and writes the output:

> > > ...
> > >        for _, route := range config.Routes {
> > >                url, _ := url.Parse(route.origin)
> > >                MustacheHandler :=
> NewMustacheHandler(route.TemplateCache,
> > > url)
> > >                http.Handle(route.Pattern, MustacheHandler)
> > >        }
> > >        err = http.ListenAndServe(address, nil)
> > >        if err != nil {
> > >                log.Fatal("ListenAndServe: ", err)
> > >        }
> > > ...

> > > The mustache handler looks a little bit like this:

> > > func NewMustacheHandler(template []byte, url *url.URL)
> > > http.HandlerFunc {
> > >    return func(w http.ResponseWriter, r *http.Request) {
> > >        mw := NewMustacheWriter(w, template)
> > >        rw := mustacheResponseWriter{Writer: mw, ResponseWriter: w}

> > >        proxy := httputil.NewSingleHostReverseProxy(url)
> > >        proxy.ServeHTTP(rw, r)

> > The actual URL is created by combining r with url.  Just do an http.Get
> on
> > URL unless you actually want a reverse proxy for a directory or
> something.

> > >        }
> > > }

> > > And the mustache writer looky likey thisy:

> > > type MustacheWriter struct {
> > >        Template []byte
> > >        w io.Writer
> > > }

> > > func (w MustacheWriter) Write(b []byte) (int, error) {
> > >        var f interface{}
> > >        err := json.Unmarshal(b, &f)
> > >        if err != nil {
> > >                        log.Fatal(err, string(b))
> > >        }

> > >        m := f.(map[string]interface{})
> > >        d := mustache.Render(string(w.Template), m)

> > >    return w.Write([]byte(d))
> > > }

> > > The problem is that I keep getting "File not found" passed into the
> > > Write(b []byte) argument, even though if I curl the URL being passed
> > > as the origin I get valid JSON back.

> > > So, questions!

> > > 1) Am I using NewSingleHostReverseProxy() correctly?

> > 2) Is there a problem with my approach to this problem?

> > > 3) Is there a better way?

> > > Cheers!
> > > Ben

> > The route URL is being modified by ReverseProxy
> Ah, interesting! Why does it do that!?

> Hi Gophers!

> Messing about with a small project: it's basically a reverse proxy
> that will convert json responses from the origin server to lovely html
> in the client request. It decodes the json response from the origin
> and passes this struct to the mustache templating engine which outputs
> html.

> The server has a config file allowing the user to specify url patterns
> to match and destination urls to proxy to:
> {
>    "pattern":"/hello",
>    "origin":"http://example.com/some/destination",
>    "template":"./hello.template"
> } // etc, etc

> I'm having difficulty understanding our friend
> httputil.NewSingleHostReverseProxy(). It may have something to do with
> the way I have approached this though.

> Ideally I have a http server. This assigns a handler for each entry in
> the config file, matched by pattern. The handler creates a new proxy
> server using httputil.NewSingleHostReverseProxy() with the origin
> config parameter as the target argument. I then have a custom
> http.RequestWriter that reads the json body in response, parses it,
> passes it to mustache and writes the output:

> ...
>         for _, route := range config.Routes {
>                 url, _ := url.Parse(route.origin)
>                 MustacheHandler := NewMustacheHandler(route.TemplateCache,
> url)
>                 http.Handle(route.Pattern, MustacheHandler)
>         }
>         err = http.ListenAndServe(address, nil)
>         if err != nil {
>                 log.Fatal("ListenAndServe: ", err)
>         }
> ...

> The mustache handler looks a little bit like this:

> func NewMustacheHandler(template []byte, url *url.URL)
> http.HandlerFunc {
>     return func(w http.ResponseWriter, r *http.Request) {
>         mw := NewMustacheWriter(w, template)
>         rw := mustacheResponseWriter{Writer: mw, ResponseWriter: w}

>         proxy := httputil.NewSingleHostReverseProxy(url)
>         proxy.ServeHTTP(rw, r)
>         }
> }

> And the mustache writer looky likey thisy:

> type MustacheWriter struct {
>         Template []byte
>         w io.Writer
> }

> func (w MustacheWriter) Write(b []byte) (int, error) {
>         var f interface{}
>         err := json.Unmarshal(b, &f)
>         if err != nil {
>                         log.Fatal(err, string(b))
>         }

>         m := f.(map[string]interface{})
>         d := mustache.Render(string(w.Template), m)

>     return w.Write([]byte(d))
> }

> The problem is that I keep getting "File not found" passed into the
> Write(b []byte) argument, even though if I curl the URL being passed
> as the origin I get valid JSON back.

> So, questions!

> 1) Am I using NewSingleHostReverseProxy() correctly?
> 2) Is there a problem with my approach to this problem?
> 3) Is there a better way?

> Cheers!
> Ben