chore(allsrv): add implementation of allsrv server

This server represents a server with minimum abstraction. It takes the
popular convention from the Matt Ryer post and implements it in an intensely
terse manner.

Explore this allsrv pkg and answer the following questions:

Question: What stands out?
Question: What do you find favorable?
Question: What do you find nasueating?

Refs: [How I write HTTP Services After 8 Years - Matt Ryer](https://pace.dev/blog/2018/05/09/how-I-write-http-services-after-eight-years.html)

allsrv/server.go

@@ -0,0 +1,166 @@
+package allsrv
+
+import (
+	"encoding/json"
+	"errors"
+	"log"
+	"net/http"
+
+	"github.com/gofrs/uuid"
+)
+
+type Server struct {
+	db *inmemDB
+
+	user, pass string
+}
+
+func NewServer(db *inmemDB, user, pass string) *Server {
+	s := Server{
+		db:   db,
+		user: user,
+		pass: pass,
+	}
+	s.routes()
+	return &s
+}
+
+func (s *Server) routes() {
+	http.Handle("POST /foo", http.HandlerFunc(s.createFoo))
+	http.Handle("GET /foo", http.HandlerFunc(s.readFoo))
+	http.Handle("PUT /foo", http.HandlerFunc(s.updateFoo))
+	http.Handle("DELETE /foo", http.HandlerFunc(s.delFoo))
+}
+
+func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	http.DefaultServeMux.ServeHTTP(w, r)
+}
+
+type Foo struct {
+	ID   string `json:"id" gorm:"id"`
+	Name string `json:"name" gorm:"name"`
+	Note string `json:"note" gorm:"note"`
+}
+
+func (s *Server) createFoo(w http.ResponseWriter, r *http.Request) {
+	if user, pass, ok := r.BasicAuth(); !(ok && user == s.user && pass == s.pass) {
+		w.WriteHeader(http.StatusUnauthorized)
+		return
+	}
+
+	var f Foo
+	if err := json.NewDecoder(r.Body).Decode(&f); err != nil {
+		w.WriteHeader(http.StatusForbidden)
+		return
+	}
+
+	newFooID, err := s.db.createFoo(f)
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	f, err = s.db.readFoo(newFooID)
+	if err != nil {
+		w.WriteHeader(http.StatusNotFound)
+		return
+	}
+
+	w.WriteHeader(http.StatusCreated)
+	if err := json.NewEncoder(w).Encode(f); err != nil {
+		log.Printf("unexpected error writing json value to response body: " + err.Error())
+	}
+}
+
+func (s *Server) readFoo(w http.ResponseWriter, r *http.Request) {
+	if user, pass, ok := r.BasicAuth(); !(ok && user == s.user && pass == s.pass) {
+		w.WriteHeader(http.StatusUnauthorized)
+		return
+	}
+
+	f, err := s.db.readFoo(r.URL.Query().Get("id"))
+	if err != nil {
+		w.WriteHeader(http.StatusNotFound)
+		return
+	}
+
+	if err := json.NewEncoder(w).Encode(f); err != nil {
+		log.Printf("unexpected error writing json value to response body: " + err.Error())
+	}
+}
+
+func (s *Server) updateFoo(w http.ResponseWriter, r *http.Request) {
+	if user, pass, ok := r.BasicAuth(); !(ok && user == s.user && pass == s.pass) {
+		w.WriteHeader(http.StatusUnauthorized)
+		return
+	}
+
+	var f Foo
+	if err := json.NewDecoder(r.Body).Decode(&f); err != nil {
+		w.WriteHeader(http.StatusForbidden)
+		return
+	}
+
+	if err := s.db.updateFoo(f); err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+}
+
+func (s *Server) delFoo(w http.ResponseWriter, r *http.Request) {
+	if user, pass, ok := r.BasicAuth(); !(ok && user == s.user && pass == s.pass) {
+		w.WriteHeader(http.StatusUnauthorized)
+		return
+	}
+
+	if err := s.db.delFoo(r.URL.Query().Get("id")); err != nil {
+		w.WriteHeader(http.StatusNotFound)
+		return
+	}
+}
+
+type inmemDB struct {
+	m []Foo
+}
+
+func (db *inmemDB) createFoo(f Foo) (string, error) {
+	f.ID = uuid.Must(uuid.NewV4()).String()
+
+	for _, existing := range db.m {
+		if f.Name == existing.Name {
+			return "", errors.New("foo " + f.Name + " exists")
+		}
+	}
+
+	db.m = append(db.m, f)
+
+	return f.ID, nil
+}
+
+func (db *inmemDB) readFoo(id string) (Foo, error) {
+	for _, f := range db.m {
+		if id == f.ID {
+			return f, nil
+		}
+	}
+	return Foo{}, errors.New("foo not found for id: " + id)
+}
+
+func (db *inmemDB) updateFoo(f Foo) error {
+	for i, existing := range db.m {
+		if f.ID == existing.ID {
+			db.m[i] = f
+			return nil
+		}
+	}
+	return errors.New("foo not found for id: " + f.ID)
+}
+
+func (db *inmemDB) delFoo(id string) error {
+	for i, f := range db.m {
+		if id == f.ID {
+			db.m = append(db.m[:i], db.m[i+1:]...)
+		}
+	}
+	return errors.New("foo not found for id: " + id)
+}

go.mod

@@ -0,0 +1,5 @@
+module mess
+
+go 1.22
+
+require github.com/gofrs/uuid v4.4.0+incompatible

go.sum

@@ -0,0 +1,2 @@
+github.com/gofrs/uuid v4.4.0+incompatible h1:3qXRTX8/NbyulANqlc0lchS1gqAVxRgsuW1YrTJupqA=
+github.com/gofrs/uuid v4.4.0+incompatible/go.mod h1:b2aQJv3Z4Fp6yNu3cdSllBxTCLRxnplIgP/c0N/04lM=