Merge pull request #3 from speakeasy-api/feat/spe-1358

add offset/limit pagination

Author: alexadrake

cmd/server/main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"github.com/speakeasy-api/speakeasy-auth-test-service/internal/pagination"
 	"github.com/speakeasy-api/speakeasy-auth-test-service/internal/responseHeaders"
 	"log"
 	"net/http"
@@ -18,6 +19,8 @@ func main() {
 	r.HandleFunc("/auth", auth.HandleAuth).Methods(http.MethodPost)
 	r.HandleFunc("/requestbody", requestbody.HandleRequestBody).Methods(http.MethodPost)
 	r.HandleFunc("/vendorjson", responseHeaders.HandleVendorJsonResponseHeaders).Methods(http.MethodGet)
+	r.HandleFunc("/pagination/limitoffset/page", pagination.HandleLimitOffsetPage).Methods(http.MethodGet, http.MethodPut)
+	r.HandleFunc("/pagination/limitoffset/offset", pagination.HandleLimitOffsetOffset).Methods(http.MethodGet, http.MethodPut)
 
 	log.Println("Listening on :8080")
 	if err := http.ListenAndServe(":8080", r); err != nil {

internal/pagination/service.go

@@ -0,0 +1,108 @@
+package pagination
+
+import (
+	"encoding/json"
+	"net/http"
+	"strconv"
+)
+
+type PaginationRequest struct {
+	Limit  int `json:"limit"`
+	Offset int `json:"offset"`
+	Page   int `json:"page"`
+}
+
+type PaginationResponse struct {
+	NumPages     int   `json:"numPages"`
+	ResultsArray []int `json:"resultsArray"`
+}
+
+const total = 20
+
+func HandleLimitOffsetPage(w http.ResponseWriter, r *http.Request) {
+	queryLimit := r.FormValue("limit")
+	queryPage := r.FormValue("page")
+
+	var pagination PaginationRequest
+	hasBody := true
+	if err := json.NewDecoder(r.Body).Decode(&pagination); err != nil {
+		hasBody = false
+	}
+	limit, err := getValue(queryLimit, hasBody, pagination.Limit, w)
+	if err != nil {
+		return
+	}
+	page, err := getValue(queryPage, hasBody, pagination.Page, w)
+	if err != nil {
+		return
+	}
+
+	start := (page - 1) * limit
+	if start > total {
+		w.WriteHeader(404)
+	}
+
+	res := PaginationResponse{
+		NumPages:     total / limit,
+		ResultsArray: make([]int, 0),
+	}
+
+	for i := start; i < total && len(res.ResultsArray) < limit; i++ {
+		res.ResultsArray = append(res.ResultsArray, i)
+	}
+
+	err = json.NewEncoder(w).Encode(res)
+	if err != nil {
+		w.WriteHeader(500)
+	}
+}
+
+func HandleLimitOffsetOffset(w http.ResponseWriter, r *http.Request) {
+	queryLimit := r.FormValue("limit")
+	queryOffset := r.FormValue("offset")
+
+	var pagination PaginationRequest
+	hasBody := true
+	if err := json.NewDecoder(r.Body).Decode(&pagination); err != nil {
+		hasBody = false
+	}
+	limit, err := getValue(queryLimit, hasBody, pagination.Limit, w)
+	if err != nil {
+		return
+	}
+	offset, err := getValue(queryOffset, hasBody, pagination.Offset, w)
+	if err != nil {
+		return
+	}
+
+	if offset > total {
+		w.WriteHeader(404)
+	}
+
+	res := PaginationResponse{
+		NumPages:     total / limit,
+		ResultsArray: make([]int, 0),
+	}
+
+	for i := offset; i < total && len(res.ResultsArray) < limit; i++ {
+		res.ResultsArray = append(res.ResultsArray, i)
+	}
+
+	err = json.NewEncoder(w).Encode(res)
+	if err != nil {
+		w.WriteHeader(500)
+	}
+}
+
+func getValue(queryValue string, hasBody bool, paginationValue int, w http.ResponseWriter) (int, error) {
+	if hasBody && queryValue == "" {
+		return paginationValue, nil
+	} else {
+		value, err := strconv.Atoi(queryValue)
+		if err != nil {
+			w.WriteHeader(400)
+			return 0, err
+		}
+		return value, nil
+	}
+}