server/admin/api/handlers.go

package api

import (
	"encoding/json"
	"fmt"
	"io"
	"log"
	"net/http"
	"strconv"

	"srs.epita.fr/fic-server/libfic"

	"github.com/julienschmidt/httprouter"
)


type DispatchFunction func(httprouter.Params, []byte) (interface{}, error)

func apiHandler(f DispatchFunction) func(http.ResponseWriter, *http.Request, httprouter.Params) {
	return func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
		log.Printf("Handling %s request from %s: %s [%s]\n", r.Method, r.RemoteAddr, r.URL.Path, r.UserAgent())

		w.Header().Set("Content-Type", "application/json")

		var ret interface{}
		var err error = nil

		// Read the body
		if r.ContentLength < 0 || r.ContentLength > 6553600 {
			http.Error(w, fmt.Sprintf("{errmsg:\"Request too large or request size unknown\"}", err), http.StatusRequestEntityTooLarge)
			return
		}
		var body []byte
		if r.ContentLength > 0 {
			tmp := make([]byte, 1024)
			for {
				n, err := r.Body.Read(tmp)
				for j := 0; j < n; j++ {
					body = append(body, tmp[j])
				}
				if err != nil || n <= 0 {
					break
				}
			}
		}

		ret, err = f(ps, body)

		// Format response
		resStatus := http.StatusOK
		if err != nil {
			ret = map[string]string{"errmsg": err.Error()}
			resStatus = http.StatusBadRequest
			log.Println(r.RemoteAddr, resStatus, err.Error())
		}

		if ret == nil {
			ret = map[string]string{"errmsg": "Page not found"}
			resStatus = http.StatusNotFound
		}

		if str, found := ret.(string); found {
			w.WriteHeader(resStatus)
			io.WriteString(w, str)
		} else if bts, found := ret.([]byte); found {
			w.WriteHeader(resStatus)
			w.Write(bts)
		} else if j, err := json.Marshal(ret); err != nil {
			http.Error(w, fmt.Sprintf("{\"errmsg\":\"%q\"}", err), http.StatusInternalServerError)
		} else {
			w.WriteHeader(resStatus)
			w.Write(j)
		}
	}
}

func teamPublicHandler(f func(*fic.Team,[]byte) (interface{}, error)) func (httprouter.Params,[]byte) (interface{}, error) {
	return func (ps httprouter.Params, body []byte) (interface{}, error) {
		if tid, err := strconv.Atoi(string(ps.ByName("tid"))); err != nil {
			if team, err := fic.GetTeamByInitialName(ps.ByName("tid")); err != nil {
				return nil, err
			} else {
				return f(&team, body)
			}
		} else if tid == 0 {
			return f(nil, body)
		} else if team, err := fic.GetTeam(tid); err != nil {
			return nil, err
		} else {
			return f(&team, body)
		}
	}
}

func teamHandler(f func(fic.Team,[]byte) (interface{}, error)) func (httprouter.Params,[]byte) (interface{}, error) {
	return func (ps httprouter.Params, body []byte) (interface{}, error) {
		if tid, err := strconv.Atoi(string(ps.ByName("tid"))); err != nil {
			if team, err := fic.GetTeamByInitialName(ps.ByName("tid")); err != nil {
				return nil, err
			} else {
				return f(team, body)
			}
		} else if team, err := fic.GetTeam(tid); err != nil {
			return nil, err
		} else {
			return f(team, body)
		}
	}
}

func themeHandler(f func(fic.Theme,[]byte) (interface{}, error)) func (httprouter.Params,[]byte) (interface{}, error) {
	return func (ps httprouter.Params, body []byte) (interface{}, error) {
		if thid, err := strconv.Atoi(string(ps.ByName("thid"))); err != nil {
			return nil, err
		} else if theme, err := fic.GetTheme(thid); err != nil {
			return nil, err
		} else {
			return f(theme, body)
		}
	}
}

func exerciceHandler(f func(fic.Exercice,[]byte) (interface{}, error)) func (httprouter.Params,[]byte) (interface{}, error) {
	return func (ps httprouter.Params, body []byte) (interface{}, error) {
		if eid, err := strconv.Atoi(string(ps.ByName("eid"))); err != nil {
			return nil, err
		} else if exercice, err := fic.GetExercice(int64(eid)); err != nil {
			return nil, err
		} else {
			return f(exercice, body)
		}
	}
}

func themedExerciceHandler(f func(fic.Theme,fic.Exercice,[]byte) (interface{}, error)) func (httprouter.Params,[]byte) (interface{}, error) {
	return func (ps httprouter.Params, body []byte) (interface{}, error) {
		var theme fic.Theme
		var exercice fic.Exercice

		themeHandler(func (th fic.Theme, _[]byte) (interface{}, error) {
			theme = th
			return nil,nil
		})(ps, body)

		exerciceHandler(func (ex fic.Exercice, _[]byte) (interface{}, error) {
			exercice = ex
			return nil,nil
		})(ps, body)

		return f(theme, exercice, body)
	}
}

func notFound(ps httprouter.Params, _ []byte) (interface{}, error) {
	return nil, nil
}