Browser shows previous response

Question

I run the code

package main

import (
    "fmt"
    "net/http"
)

func main() {
    http.HandleFunc("/", sroot)
    http.ListenAndServe(":8080", nil)
}

func sroot(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintf(w, "Welcome")
}

and browser showed a response as expected: Welcome then, after some time I try to change the output but have found that the output does not change! so, when I change the output fmt.Fprintf(w, "Welcome 123") but browser still ouptuts Welcome.

So what's the magic happens here?

I restarted a program, but how to restart a server? And I run it from IDE. — user8049659, Jan 02 '19 at 12:37
The answer of @dan-esparza is likely to be correct, you can check this question to see how to debug if the browser used cache or not in chrome: https://stackoverflow.com/questions/13140318/check-whether-network-response-is-coming-from-server-or-chrome-cache — thst, Jan 02 '19 at 13:01
@thst disabling a browser cache does not solve the issue, but I was able to run it with different port adress, but againe if I want to change the output even with the new port adress the response does not change. — user8049659, Jan 02 '19 at 13:14
@user8049659 there would be a refresh icon on IDE which will restart the server, try it. — saddam, Jan 02 '19 at 13:21
@user8049659 I tried your code and it works for me in goland. Add a line `log.Print("received call")` in your `sroot` func. This will tell you if there is a cache issue or something other. — thst, Jan 02 '19 at 13:36
@thst Added it before fmt.Fprintf... restarted, then changed response and again restarted - nothing changed — user8049659, Jan 02 '19 at 13:44
You should see the log message for each request. like this `2019/01/02 14:39:05 received call` — thst, Jan 02 '19 at 13:45

score 2 · Answer 1 · answered Jan 02 '19 at 12:41

2

By default the browser makes a GET request when navigating to the page. The browser is also going to make some decisions about the 'cachability' of the page: Has the url changed? Has the querystring changed? Has the ETAG changed? If none of these are true, the browser is most likely serving a cached version of the page.

answered Jan 02 '19 at 12:41

Dan Esparza

28,047
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ETag doesn't work like that. The browser doesn't know if the ETag has changed until it makes another request, which will include If-None-Match if the ETag is known. The *server* then gets to decide if it returns 304 Not Modified or new content. Also cacheability is controlled by Cache-Control and Expires. – Adrian Jan 02 '19 at 15:11

score 0 · Answer 2 · answered Jan 02 '19 at 12:41

0

You can use gin to reload your webserver.

Installation: go get github.com/codegangsta/gin

Usage: gin run filename.go

Reference: https://github.com/codegangsta/gin

answered Jan 02 '19 at 12:41

Raja G

5,973
14
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Installed it, created folder in `src` named `webserver` and there is a main file, so then I call it `gin run webserver.go` it shows me `[gin] Listening on port 3000 [gin] Building... [gin] ←[97;32;1mBuild finished←[0m` but the browser output is the same as was before even after reloading the browser tab. – user8049659 Jan 02 '19 at 12:57

Browser shows previous response

2 Answers2