Push demo code to share with interviewers

cmd/demo.go

@@ -0,0 +1,22 @@
+package main
+
+import (
+	"fmt"
+
+	"dread.land/deepgram-demo/internal/apiServer"
+	"dread.land/deepgram-demo/internal/audio"
+	"dread.land/deepgram-demo/internal/metadata"
+)
+
+func main() {
+	fmt.Println("Hello, World!")
+
+	// would be better off as config
+	audioStorage := audio.NewAudioMemoryStorage()
+	metadataStorage := metadata.NewMetadataMemoryStorage()
+	audioServer := &audio.AudioServer{Storage: audioStorage, Metadata: metadataStorage}
+	metadataServer := &metadata.MetadataServer{Storage: metadataStorage}
+	apiServer := &apiServer.ApiServer{Audio: audioServer, Metadata: metadataServer}
+
+	apiServer.Serve()
+}

go.mod

@@ -0,0 +1,9 @@
+module dread.land/deepgram-demo
+
+go 1.19
+
+require (
+	github.com/go-audio/audio v1.0.0 // indirect
+	github.com/go-audio/riff v1.0.0 // indirect
+	github.com/go-audio/wav v1.1.0
+)

internal/apiServer/apiServer.go

@@ -0,0 +1,106 @@
+package apiServer
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+	"path"
+	"strconv"
+
+	"dread.land/deepgram-demo/internal/audio"
+	"dread.land/deepgram-demo/internal/metadata"
+)
+
+type ApiServer struct {
+	Audio    *audio.AudioServer
+	Metadata *metadata.MetadataServer
+}
+
+func (apiServer *ApiServer) filesHandler(w http.ResponseWriter, r *http.Request) {
+
+	filename := path.Base(r.URL.Path)
+	switch r.Method {
+	case "GET":
+		// get file
+		contents, err := apiServer.Audio.Download(filename)
+		if err != nil {
+			http.Error(w, fmt.Sprint(err), http.StatusNotFound)
+			return
+		}
+		w.Write(contents)
+		return
+	case "POST": // save file
+		contents, err := io.ReadAll(r.Body)
+		if err != nil {
+			http.Error(w, fmt.Sprint(err), http.StatusBadRequest)
+		}
+		err = apiServer.Audio.Upload(filename, contents)
+		if err != nil {
+			http.Error(w, fmt.Sprint(err), http.StatusConflict)
+		}
+		return
+	default:
+		// error unsupported
+		http.Error(w, "unsupported", http.StatusMethodNotAllowed)
+		return
+	}
+}
+
+func (apiServer *ApiServer) metadataHandler(w http.ResponseWriter, r *http.Request) {
+	filename := path.Base(r.URL.Path)
+	switch r.Method {
+	case "GET":
+		// get metadata
+		meta, err := apiServer.Metadata.Info(filename)
+		if err != nil {
+			http.Error(w, fmt.Sprint(err), http.StatusNotFound)
+			return
+		}
+		response, err := json.Marshal(meta)
+		if err != nil {
+			http.Error(w, fmt.Sprint(err), http.StatusInternalServerError)
+			return
+		}
+		fmt.Fprint(w, string(response))
+		return
+	default:
+		http.Error(w, "unsupported", http.StatusMethodNotAllowed)
+		return
+	}
+}
+
+func (apiServer *ApiServer) listHandler(w http.ResponseWriter, r *http.Request) {
+	maxdurationString := r.URL.Query().Get("maxduration")
+	maxduration := 0
+	var err error
+	if maxdurationString != "" {
+		maxduration, err = strconv.Atoi(maxdurationString)
+	}
+	if err != nil {
+		http.Error(w, fmt.Sprint(err), http.StatusBadRequest)
+		return // error Bad Request
+	}
+	list := apiServer.Metadata.List(maxduration)
+	response, err := json.Marshal(list)
+	if err != nil {
+		http.Error(w, fmt.Sprint(err), http.StatusInternalServerError)
+		return
+	}
+	fmt.Fprint(w, string(response))
+}
+
+func (apiServer *ApiServer) Serve() {
+
+	// POST and GET media
+	http.HandleFunc("/files/", apiServer.filesHandler)
+	// list media
+	http.HandleFunc("/files", apiServer.listHandler)
+	// list metadata (with filter)
+	http.HandleFunc("/metadata", apiServer.listHandler)
+	// GET metadata
+	http.HandleFunc("/metadata/", apiServer.metadataHandler)
+
+	log.Fatal(http.ListenAndServe(":3030", nil))
+}

internal/audio/audioServer.go

@@ -0,0 +1,42 @@
+package audio
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+
+	"github.com/go-audio/wav"
+
+	"dread.land/deepgram-demo/internal/metadata"
+)
+
+type AudioServer struct {
+	Storage  *AudioMemoryStorage
+	Metadata *metadata.MetadataMemoryStorage
+}
+
+func (a *AudioServer) Upload(filename string, contents []byte) error {
+	fmt.Println(a)
+
+	// extract duration and save as metadata
+	r := bytes.NewReader(contents)
+	decoder := wav.NewDecoder(r)
+	if !decoder.IsValidFile() {
+		return errors.New("invalid wav file")
+	}
+	dur, err := decoder.Duration()
+	if err != nil {
+		return err
+	}
+	err = a.Metadata.Put(metadata.AudioMetadata{FileName: filename, Duration: int(dur.Milliseconds())})
+	if err != nil {
+		return err
+	}
+	err = a.Storage.put(AudioFile{FileName: filename, Contents: contents})
+	return err
+}
+
+func (a *AudioServer) Download(filename string) ([]byte, error) {
+	file, err := a.Storage.get(filename)
+	return file.Contents, err
+}

internal/audio/audioStorage.go

@@ -0,0 +1,35 @@
+package audio
+
+import (
+	"errors"
+)
+
+type AudioFile struct {
+	FileName string
+	Contents []byte
+}
+
+type AudioMemoryStorage struct {
+	Data map[string]AudioFile
+}
+
+func NewAudioMemoryStorage() *AudioMemoryStorage {
+	return &AudioMemoryStorage{Data: map[string]AudioFile{}}
+}
+
+func (audio *AudioMemoryStorage) put(a AudioFile) (err error) {
+	_, ok := audio.Data[a.FileName]
+	if !ok {
+		audio.Data[a.FileName] = a
+		return nil
+	}
+	return errors.New("already exists")
+}
+
+func (audio *AudioMemoryStorage) get(filename string) (a AudioFile, err error) {
+	val, ok := audio.Data[filename]
+	if ok {
+		return val, nil
+	}
+	return AudioFile{}, errors.New("not found")
+}

internal/metadata/metadataServer.go

@@ -0,0 +1,18 @@
+package metadata
+
+type MetadataServer struct {
+	Storage *MetadataMemoryStorage
+}
+
+func (m *MetadataServer) Info(filename string) (AudioMetadata, error) {
+	a, err := m.Storage.get(filename)
+	if err == nil {
+		return a, nil
+	}
+	return AudioMetadata{}, err
+}
+
+func (m *MetadataServer) List(maxduration int) []string {
+	a := m.Storage.filterMaxDuration(maxduration)
+	return a
+}

internal/metadata/metadataStorage.go

@@ -0,0 +1,47 @@
+package metadata
+
+import (
+	"errors"
+	"fmt"
+)
+
+type AudioMetadata struct {
+	FileName string `json:"filename"`
+	Duration int    `json:"duration"`
+}
+
+type MetadataMemoryStorage struct {
+	Metadata map[string]AudioMetadata
+}
+
+func NewMetadataMemoryStorage() *MetadataMemoryStorage {
+	return &MetadataMemoryStorage{Metadata: map[string]AudioMetadata{}}
+}
+
+func (metadata *MetadataMemoryStorage) Put(a AudioMetadata) (err error) {
+	fmt.Println(metadata, a)
+	_, ok := metadata.Metadata[a.FileName]
+	if !ok {
+		metadata.Metadata[a.FileName] = a
+		return nil
+	}
+	return errors.New("already exists") // 409 Conflict
+}
+
+func (metadata *MetadataMemoryStorage) get(filename string) (a AudioMetadata, err error) {
+	val, ok := metadata.Metadata[filename]
+	if ok {
+		return val, nil
+	}
+	return AudioMetadata{}, errors.New("not found") // 404 Not Found
+}
+
+func (metadata *MetadataMemoryStorage) filterMaxDuration(maxDuration int) (a []string) {
+	result := []string{}
+	for _, item := range metadata.Metadata {
+		if (item.Duration <= maxDuration) || (maxDuration <= 0) {
+			result = append(result, item.FileName)
+		}
+	}
+	return result
+}