go panic - No data received - ERR_EMPTY_RESPONSE

I'm using gorethink driver, I write a query function like this in model

func GetQuotesByUser(idUser string) []Quote{
    ids:=GetQuoteIdsByUser(idUser)
    if (len(ids)>0){
        result,err:=r.Table("quote").GetAll(ids...).Run(config.Connection())
        defer result.Close()

        if err!=nil{
            fmt.Println(err)
            return []Quote{}
        }
        var quotes []Quote
        err=result.All(&quotes)
        if err!=nil{
            fmt.Println(err)
            return []Quote{}
        }
        fmt.Println(quotes)
        return quotes
    } else{
        return []Quote{}
    }
}

I write a route handler that calls the above function

import (
    "corate/util"
    "corate/model"
    "github.com/fatih/structs"
    "net/http"
)

func DashboardHandler(w http.ResponseWriter,r *http.Request){
    files:=[]string{"base","dashboard"}
    session,_:=util.GlobalSessions.SessionStart(w,r)
    defer session.SessionRelease(w)
    quotes:=model.GetQuotesByUser("ca8a2e14-f65b-43b1-b655-97d7c29190ec")
    q:=structs.Map(quotes)
    util.RenderTemplate(w,q,files...)
}

This is main function

func main(){

    // Setup database

    config.Setupdb()

    // Initialize session manager

    util.InitSessionManager()

    // Serve static folder

    http.Handle("/public/",http.StripPrefix("/public/",http.FileServer(http.Dir("public"))))

    // Setup routers and middlewares

    http.HandleFunc("/",route.IndexHandler)
    http.HandleFunc("/login",route.GoogleLoginHandler)
    http.HandleFunc("/auth/google",route.GoogleCallbackHandler)

    http.Handle("/dashboard",negroni.New(
        negroni.HandlerFunc(route.IsAuthenticated),
        negroni.Wrap(http.HandlerFunc(route.DashboardHandler)),
    ))

    // Start listening

    http.ListenAndServe(":3000",nil)
}

I use astaxie/beego/session library to manage sessions for this server

import (
    "github.com/astaxie/beego/session"
)

var (
    GlobalSessions *session.Manager
)

func InitSessionManager() {
    GlobalSessions, _ = session.NewManager("memory", `{"cookieName":"gosessionid","gclifetime":3600}`)
    go GlobalSessions.GC()
}

When I start the server, and login and request to dashboard path, DashboardHandler is processed,GetQuotesByUser is called, and it works, it works, it does print out true results of query. But in browser, the browser throws error:

No data received

ERR_EMPTY_RESPONSE

The console logs some errors as well

http: panic serving 127.0.0.1:51229: not struct
goroutine 84 [running]:
net/http.(*conn).serve.func1(0xc82015fc00)
    /home/kuro/.gvm/gos/go1.6/src/net/http/server.go:1389 +0xc1
panic(0x7f58e0, 0xc8204489f0)
    /home/kuro/.gvm/gos/go1.6/src/runtime/panic.go:426 +0x4e9
github.com/fatih/structs.strctVal(0x7de700, 0xc82045a340, 0x0, 0x0, 0x0)
    /home/kuro/Workspace/Go/src/github.com/fatih/structs/structs.go:426 +0x136
github.com/fatih/structs.New(0x7de700, 0xc82045a340, 0x0)
    /home/kuro/Workspace/Go/src/github.com/fatih/structs/structs.go:30 +0x2f
github.com/fatih/structs.Map(0x7de700, 0xc82045a340, 0xc82045a340)
    /home/kuro/Workspace/Go/src/github.com/fatih/structs/structs.go:435 +0x2b
corate/route.DashboardHandler(0x7fe2c2e6dfc8, 0xc8202d49c0, 0xc820372460)
    /home/kuro/Workspace/Go/src/corate/route/user.go:19 +0x190
net/http.HandlerFunc.ServeHTTP(0xa47820, 0x7fe2c2e6dfc8, 0xc8202d49c0, 0xc820372460)
    /home/kuro/.gvm/gos/go1.6/src/net/http/server.go:1618 +0x3a
github.com/codegangsta/negroni.Wrap.func1(0x7fe2c2e6dfc8, 0xc8202d49c0, 0xc820372460, 0xc8203f0a60)
    /home/kuro/Workspace/Go/src/github.com/codegangsta/negroni/negroni.go:41 +0x50
github.com/codegangsta/negroni.HandlerFunc.ServeHTTP(0xc82012ace0, 0x7fe2c2e6dfc8, 0xc8202d49c0, 0xc820372460, 0xc8203f0a60)
    /home/kuro/Workspace/Go/src/github.com/codegangsta/negroni/negroni.go:24 +0x44
github.com/codegangsta/negroni.middleware.ServeHTTP(0x7fe2c2e6ade0, 0xc82012ace0, 0xc82012ad40, 0x7fe2c2e6dfc8, 0xc8202d49c0, 0xc820372460)
    /home/kuro/Workspace/Go/src/github.com/codegangsta/negroni/negroni.go:33 +0xaa
github.com/codegangsta/negroni.(middleware).ServeHTTP-fm(0x7fe2c2e6dfc8, 0xc8202d49c0, 0xc820372460)
    /home/kuro/Workspace/Go/src/github.com/codegangsta/negroni/negroni.go:33 +0x53
corate/route.IsAuthenticated(0x7fe2c2e6dfc8, 0xc8202d49c0, 0xc820372460, 0xc8203f0a00)
    /home/kuro/Workspace/Go/src/corate/route/isAuthenticated.go:14 +0x174
github.com/codegangsta/negroni.HandlerFunc.ServeHTTP(0xa47840, 0x7fe2c2e6dfc8, 0xc8202d49c0, 0xc820372460, 0xc8203f0a00)
    /home/kuro/Workspace/Go/src/github.com/codegangsta/negroni/negroni.go:24 +0x44
github.com/codegangsta/negroni.middleware.ServeHTTP(0x7fe2c2e6ade0, 0xa47840, 0xc82012ad20, 0x7fe2c2e6dfc8, 0xc8202d49c0, 0xc820372460)
    /home/kuro/Workspace/Go/src/github.com/codegangsta/negroni/negroni.go:33 +0xaa
github.com/codegangsta/negroni.(*Negroni).ServeHTTP(0xc8200cfe90, 0x7fe2c2e6af70, 0xc820154680, 0xc820372460)
    /home/kuro/Workspace/Go/src/github.com/codegangsta/negroni/negroni.go:73 +0x122
net/http.(*ServeMux).ServeHTTP(0xc820013740, 0x7fe2c2e6af70, 0xc820154680, 0xc820372460)
    /home/kuro/.gvm/gos/go1.6/src/net/http/server.go:1910 +0x17d
net/http.serverHandler.ServeHTTP(0xc82000e380, 0x7fe2c2e6af70, 0xc820154680, 0xc820372460)
    /home/kuro/.gvm/gos/go1.6/src/net/http/server.go:2081 +0x19e
net/http.(*conn).serve(0xc82015fc00)
    /home/kuro/.gvm/gos/go1.6/src/net/http/server.go:1472 +0xf2e
created by net/http.(*Server).Serve
    /home/kuro/.gvm/gos/go1.6/src/net/http/server.go:2137 +0x44e

Why does it happen? Then I notice that if I don't utilize fatih/structs library, nothing will go wrong. But I want to use that library, it will help me much. I want to know reason of this strange behavior and how to fix it while still using fatih/structs library

Answers


GetQuotesByUser returns a slice, not a struct. So you can't pass it directly to structs.Map. You'll have to iterate the slice and convert each element to a map individually.

quotes := model.GetQuotesByUser("ca8a2e14-f65b-43b1-b655-97d7c29190ec")

qs := []map[string]interface{}{}
for _, q := range quotes {
    qs = append(qs, structs.Map(q))
}

util.RenderTemplate(w,qs,files...)

Should get you close to what you're after.


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