CIiP-WS-2021-2022-Projektarbeit_Lithium/controllers/upload.go

package controllers

import (
	"bytes"
	"encoding/json"
	"github.com/geplauder/lithium/pipelines"
	"github.com/geplauder/lithium/storage"
	"github.com/sirupsen/logrus"
	"io"
	"net/http"
)

func UploadHandler(w http.ResponseWriter, r *http.Request, pipes []pipelines.IPipeline, storageProvider storage.IStorageProvider) {
	// open file handler
	formFile, handler, err := r.FormFile("file")
	if err != nil {
		writeError(w, http.StatusUnprocessableEntity, err.Error())
		return
	}

	defer formFile.Close()

	// check pipelines form param
	formPipeline := r.FormValue("pipeline")
	if formPipeline == "" {
		writeError(w, http.StatusUnprocessableEntity, "pipeline parameter missing")
		return
	}

	var execPipe pipelines.IPipeline
	for _, pipe := range pipes {
		if formPipeline == pipe.GetSlug() {
			execPipe = pipe
			break
		}
	}

	if execPipe == nil {
		writeError(w, http.StatusUnprocessableEntity, "pipeline not found")
		return
	}

	bucket := r.FormValue("bucket")
	if bucket == "" {
		writeError(w, http.StatusUnprocessableEntity, "bucket parameter missing")
		return
	}

	// open file
	file, err := handler.Open()
	if err != nil {
		writeError(w, http.StatusInternalServerError, "error reading uploaded file")
		return
	}

	defer file.Close()

	// read file to buffer
	buf := bytes.NewBuffer(nil)
	_, err = io.Copy(buf, file)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "error reading file from buffer")
		return
	}

	// store uploaded file
	_, err = storageProvider.StoreRaw(bucket, "source.jpg", buf.Bytes())
	if err != nil {
		return
	}

	// execute pipeline
	output, err := execPipe.Run("source.jpg", bucket, storageProvider)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "error executing pipeline")
		return
	}

	w.Header().Set("Content-Type", "application/json")

	err = json.NewEncoder(w).Encode(struct {
		Message     string   `json:"message"`
		OutputFiles []string `json:"output_files"`
	}{"ok", []string{output}})

	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
	}

	logrus.Info("Pipeline routes registered successfully")
}