From 75c50a705f4cf2f40a8e5d7c4cb67542e9bcb117 Mon Sep 17 00:00:00 2001
From: kolaente <k@knt.li>
Date: Mon, 21 Oct 2019 23:04:17 +0200
Subject: [PATCH] Changed ReadAll method to enable proper pagination

---
 handler/config.go   |  1 +
 handler/read_all.go | 28 +++++++++++++++++++++++++---
 web.go              |  2 +-
 3 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/handler/config.go b/handler/config.go
index c568e99..8a5aaaa 100644
--- a/handler/config.go
+++ b/handler/config.go
@@ -24,6 +24,7 @@ import (
 type Config struct {
 	AuthProvider    *web.Auths
 	LoggingProvider *logging.Logger
+	MaxItemsPerPage int64
 }
 
 var config *Config
diff --git a/handler/read_all.go b/handler/read_all.go
index 1fd5db7..8e995e9 100644
--- a/handler/read_all.go
+++ b/handler/read_all.go
@@ -41,7 +41,7 @@ func (c *WebHandler) ReadAllWeb(ctx echo.Context) error {
 	if page == "" {
 		page = "1"
 	}
-	pageNumber, err := strconv.Atoi(page)
+	pageNumber, err := strconv.ParseInt(page, 10, 64)
 	if err != nil {
 		config.LoggingProvider.Error(err.Error())
 		return echo.NewHTTPError(http.StatusBadRequest, "Bad page requested.")
@@ -50,13 +50,35 @@ func (c *WebHandler) ReadAllWeb(ctx echo.Context) error {
 		return echo.NewHTTPError(http.StatusBadRequest, "Bad page requested.")
 	}
 
+	// Items per page
+	perPage := ctx.QueryParam("per_page")
+	perPageNumber, err := strconv.ParseInt(perPage, 10, 64)
+	if err != nil {
+		config.LoggingProvider.Error(err.Error())
+		return echo.NewHTTPError(http.StatusBadRequest, "Bad per page amount requested.")
+	}
+	// Set default page count
+	if perPageNumber == 0 {
+		perPageNumber = config.MaxItemsPerPage
+	}
+	if perPageNumber < 1 {
+		return echo.NewHTTPError(http.StatusBadRequest, "Bad per page amount requested.")
+	}
+	if perPageNumber > config.MaxItemsPerPage {
+		perPageNumber = config.MaxItemsPerPage
+	}
+
 	// Search
 	search := ctx.QueryParam("s")
 
-	lists, err := currentStruct.ReadAll(search, currentAuth, pageNumber)
+	result, resultCount, numberOfPages, err := currentStruct.ReadAll(currentAuth, search, pageNumber, perPageNumber)
 	if err != nil {
 		return HandleHTTPError(err, ctx)
 	}
 
-	return ctx.JSON(http.StatusOK, lists)
+	ctx.Response().Header().Set("x-pagination-total-pages", strconv.FormatInt(numberOfPages, 10))
+	ctx.Response().Header().Set("x-pagination-result-count", strconv.FormatInt(resultCount, 10))
+	ctx.Response().Header().Set("Access-Control-Expose-Headers", "x-pagination-total-pages, x-pagination-result-count")
+
+	return ctx.JSON(http.StatusOK, result)
 }
diff --git a/web.go b/web.go
index 868c367..ba126fd 100644
--- a/web.go
+++ b/web.go
@@ -31,7 +31,7 @@ type Rights interface {
 type CRUDable interface {
 	Create(Auth) error
 	ReadOne() error
-	ReadAll(string, Auth, int) (interface{}, error)
+	ReadAll(auth Auth, search string, page int64, perPage int64) (result interface{}, resultCount int64, numberOfPages int64, err error)
 	Update() error
 	Delete() error
 }