WIP: Add JSON-based API under `/api`step-re-ordering

TODO: Not all the information is provided there.

This commit provides an unstable JSON API for communication with an
upcoming Dart frontend.

Later it might be part of the public interface for integration into
other services. For this step it has to be ensured the semantics are not
changing a lot in the future which is currently out of scope.

5 files changed, 90 insertions, 0 deletions

diff --git a/model/object.go b/model/object.go
index 63ef419..0b1919b 100644
--- a/model/object.go
+++ b/model/object.go
@@ -9,4 +9,5 @@ type Object interface {
 	Read(tx *sql.Tx) error
 	Update(tx *sql.Tx) error
 	Delete(tx *sql.Tx) error
+	SetID(id int)
 }
diff --git a/model/recipe.go b/model/recipe.go
index 684b158..adcafa1 100644
--- a/model/recipe.go
+++ b/model/recipe.go
@@ -5,6 +5,8 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"log"
+	"strconv"
 )
 
 type Recipe struct {
@@ -19,11 +21,23 @@ type Recipe struct {
 	IsFavorite  bool   `json:"is_favorite"`
 }
 
+func NewRecipe() Object {
+	return &Recipe{}
+}
+
 func (r Recipe) String() string {
 	b, _ := json.MarshalIndent(r, "", "    ")
 	return string(b)
 }
 
+func (r *Recipe) SetID(id int) {
+	if r == nil {
+		log.Println("Got nil as recipe!")
+	}
+
+	r.Id = strconv.Itoa(id)
+}
+
 func (r *Recipe) Validate() error {
 	var err error
 
diff --git a/model/recipes.go b/model/recipes.go
index e4fd1b8..b711dab 100644
--- a/model/recipes.go
+++ b/model/recipes.go
@@ -14,6 +14,10 @@ type RecipesElement struct {
 
 type Recipes []RecipesElement
 
+func (r *Recipes) SetID(id int) {
+	// singleton object, ignoring ID
+}
+
 func (r *Recipes) Create(tx *sql.Tx) error {
 	return fmt.Errorf("Impossible to create a recipe list")
 }
diff --git a/server.go b/server.go
index 3868315..07389a8 100644
--- a/server.go
+++ b/server.go
@@ -30,9 +30,15 @@ func NewServer(addr string, db *model.DB) *Server {
 	mux.Handle("GET /recipes", view.RecipesRead(db))
 
 	mux.Handle("GET /recipe/create", view.RecipeCreate())
+
+	mux.Handle("POST /api/recipe", view.CreateJSON[*model.Recipe](db, model.NewRecipe))
 	mux.Handle("POST /recipe", controller.RecipeCreate(db))
+
+	mux.Handle("GET /api/recipe/{id}", view.ReadJSON[*model.Recipe](db, model.NewRecipe))
 	mux.Handle("GET /recipe/{id}", view.RecipeRead(db))
+
 	mux.Handle("POST /recipe/{id}", controller.RecipeUpdate(db))
+
 	mux.Handle("DELETE /recipe/{id}", controller.RecipeDelete(db))
 
 	mux.Handle("GET /favicon.ico", view.FaviconRead())
diff --git a/view/json.go b/view/json.go
new file mode 100644
index 0000000..5f3a30c
--- /dev/null
+++ b/view/json.go
@@ -0,0 +1,65 @@
+package view
+
+import (
+	"encoding/json"
+	"io"
+	"log"
+	"net/http"
+	"strconv"
+
+	"xengineering.eu/ceres/model"
+)
+
+func CreateJSON[O model.Object](db *model.DB, constructor func() model.Object) http.Handler {
+	return http.HandlerFunc(
+		func(w http.ResponseWriter, r *http.Request) {
+			buf, err := io.ReadAll(r.Body)
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
+
+			object := constructor()
+			err = json.Unmarshal(buf, &object)
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusBadRequest)
+				return
+			}
+
+			err = db.Transaction(object.Create)
+			if err != nil {
+				log.Println("Could not create object.")
+				http.Error(w, "Could not create object.", http.StatusBadRequest)
+				return
+			}
+		},
+	)
+}
+
+func ReadJSON[O model.Object](db *model.DB, constructor func() model.Object) http.Handler {
+	return http.HandlerFunc(
+		func(w http.ResponseWriter, r *http.Request) {
+			object := constructor()
+
+			id, err := strconv.Atoi(r.PathValue("id"))
+			if err != nil {
+				// TODO
+				return
+			}
+			object.SetID(id)
+
+			err = db.Transaction(object.Read)
+			if err != nil {
+				// TODO
+				return
+			}
+
+			w.Header().Set("Content-Type", "application/json")
+			err = json.NewEncoder(w).Encode(object)
+			if err != nil {
+				// TODO
+				return
+			}
+		},
+	)
+}