Add pagination support

main.go

@@ -22,6 +22,7 @@ func setupRouter(env *Env, spotifyID string, spotifySecret string) *gin.Engine {
 	// See: https://pkg.go.dev/github.com/gin-gonic/gin#Engine.SetTrustedProxies
 	r.SetTrustedProxies(nil)
 	r.Use(spotifyAuth(spotifyID, spotifySecret))
+	r.Use(paginator())
 	r.GET("/alive", env.alive)
 	r.GET("/artists/:artistID", env.getArtistByID)
 	r.GET("/artists", env.getArtistByName)

routes.go

@@ -6,8 +6,53 @@ import (
 	"gorm.io/gorm/clause"
 	"log/slog"
 	"net/http"
+	"strconv"
 )
 
+// Pagination helper middleware
+// This just checks and inserts some default pagination values
+func paginator() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		queryPage := c.DefaultQuery("page", "1")
+		queryPageSize := c.DefaultQuery("page_size", "10")
+
+		// add some defaults here if user gives us empty values
+		if queryPage == ""{
+			queryPage = "1"
+		}
+		if queryPageSize == "" {
+			queryPageSize = "10"
+		}
+
+		page, err := strconv.Atoi(queryPage)
+		if err != nil {
+			c.JSON(http.StatusBadRequest, gin.H{"Error": "Failed to convert page parameter to number"})
+			c.Abort()
+			return
+		}
+
+		pageSize, err := strconv.Atoi(queryPageSize)
+		if err != nil {
+			c.JSON(http.StatusBadRequest, gin.H{"Error": "Failed to convert page_size parameter to number"})
+			c.Abort()
+			return
+		}
+
+		if page < 1 || pageSize < 1 {
+			page, pageSize = 1, 10
+		}
+
+		// Calculate the correct SQL offset for this page
+		offset := (page - 1) * pageSize
+		c.Set("page", page)
+		c.Set("page_size", pageSize)
+		c.Set("page_offset", offset)
+
+		// Process request
+		c.Next()
+	}
+}
+
 func (env *Env) alive(c *gin.Context) {
 	c.String(http.StatusOK, "yes!")
 }
@@ -70,13 +115,15 @@ func (env *Env) getArtistByName(c *gin.Context) {
 		c.JSON(http.StatusBadRequest, gin.H{"Error": "name parameter was not supplied"})
 		return
 	}
+	pageSize := c.GetInt("page_size")
+	pageOffset := c.GetInt("page_offset")
 
 	// Lookup this name in the DB and return any ArtistProfile objects
 	// NOTE: This is case insensitive for ascii on sqlite
 	// NOTE: However unicode is treated case sensitive due to very difficult conversions for some languages/characters
 	// NOTE: In future better DBs with unicode support such as postgres should be used
 	var artistProfiles []ArtistProfile
-	dbResult := env.db.Where("name LIKE ?", fmt.Sprintf("%%%s%%", artistName)).Preload("Genres").Find(&artistProfiles)
+	dbResult := env.db.Where("name LIKE ?", fmt.Sprintf("%%%s%%", artistName)).Preload("Genres").Offset(pageOffset).Limit(pageSize).Find(&artistProfiles)
 	if dbResult.Error != nil {
 		slog.Error("[GOMUSIC] Failed to query local database for artist name", "Name", artistName)
 		c.JSON(http.StatusInternalServerError, gin.H{"Error": "Failed to lookup name"})
@@ -88,7 +135,10 @@ func (env *Env) getArtistByName(c *gin.Context) {
 
 func (env *Env) getGenres(c *gin.Context) {
 	var genres []Genre
-	dbResult := env.db.Find(&genres)
+	pageSize := c.GetInt("page_size")
+	pageOffset := c.GetInt("page_offset")
+
+	dbResult := env.db.Offset(pageOffset).Limit(pageSize).Find(&genres)
 	if dbResult.Error != nil {
 		slog.Error("[GOMUSIC] Failed to query local database for genre data")
 		c.JSON(http.StatusInternalServerError, gin.H{"Error": "Failed to query database for genre data"})

routes_test.go

@@ -97,7 +97,7 @@ func TestGetArtistByName(t *testing.T) {
 		assert.Fail(t, fmt.Sprintf("Could not validate and parse JSON response: %s", err.Error()))
 	}
 
-	// only response should be kanye
+	// only response should be aesop
 	assert.Equal(t, "Aesop Rock", resp[0].Name)
 	assert.Equal(t, "2fSaE6BXtQy0x7R7v9IOmZ", resp[0].SpotifyID)
 }