SFM-loan-Rest-Api/apiV1Uploads.go

package main

import (
	"biukop.com/sfm/loan"
	"crypto/sha256"
	"errors"
	"fmt"
	log "github.com/sirupsen/logrus"
	"io"
	"io/ioutil"
	"net/http"
	"os"
	"strconv"
	"strings"
	"time"
)

func apiV1UploadsGet(w http.ResponseWriter, r *http.Request, ss *loan.Session) {
	id := r.URL.Path[len(apiV1Prefix+"upload/"):] //remove prefix
	intId, e := strconv.Atoi(id)
	if e != nil {
		log.Println("invalid id for upload get", id, e)
		apiV1Client403Error(w, r, ss) // bad request
		return
	}

	ul := uploadsOnDisk{}
	e = ul.Upload.Read(int64(intId))
	if e != nil {
		log.Println("no file uploaded", intId, e)
		apiV1Client404Error(w, r, ss) // bad request
		return
	}

	//check local file first
	path := ul.filePath()
	if fileExists(path) {
		http.ServeFile(w, r, path)
		return
	}

	log.Error("Upload file not found on disk", ul)
	apiV1Server500Error(w, r) // bad request
}

func apiV1UploadsPost(w http.ResponseWriter, r *http.Request, ss *loan.Session) {
	id := r.URL.Path[len(apiV1Prefix+"lender-upload/"):] //remove prefix

	filepath, e := saveUploadToFile(r)
	if e != nil {
		log.Println("no file uploaded", filepath, e)
		apiV1Client404Error(w, r, ss) // bad request
		return
	}

	intId, e := strconv.Atoi(id)
	if id != "" {
		if e != nil {
			log.Println("Error Getting File", e)
			apiV1Client404Error(w, r, ss) // bad request
			return
		}
		updateUploads(int64(intId), filepath, w, r, ss)
	} else {
		createUploads(filepath, w, r, ss)
	}
}

func sha256File(input io.Reader) string {
	hash := sha256.New()
	if _, err := io.Copy(hash, input); err != nil {
		log.Fatal(err)
	}
	sum := hash.Sum(nil)

	return fmt.Sprintf("%x", sum)
}

func updateUploads(id int64, filePath string, w http.ResponseWriter, r *http.Request, ss *loan.Session) {
	ul := uploadsOnDisk{}
	e := ul.Upload.Read(int64(id))
	if e != nil {
		log.Println("bad upload id is given ", id, e)
		apiV1Client404Error(w, r, ss) // bad request
		return
	}

	ul1, isDuplicate, e := saveUploadsMetaToDB(id, filePath, r, ss)
	ul.Upload.IsDuplicate = isDuplicate
	if e != nil {
		os.Remove(ul.filePath())
		ul1.Delete()
		log.Println("cannot save file info to db ", e)
		apiV1Server500Error(w, r) // bad request
		return
	}

	apiV1SendJson(ul1, w, r, ss)
}

func createUploads(filePath string, w http.ResponseWriter, r *http.Request, ss *loan.Session) {
	ul := uploadsOnDisk{}
	ulMeta, isDuplicate, e := saveUploadsMetaToDB(0, filePath, r, ss)
	ul.Upload = ulMeta
	ul.Upload.IsDuplicate = isDuplicate
	if e != nil {
		log.Println("cannot save file info to db ", e)
		e = ulMeta.Delete() // delete the newly created, if failed, db will clean it
		if e != nil {
			log.Error("failed to remove unused uploads", ul)
		}

		e = os.Remove(ul.filePath())
		if e != nil {
			log.Error("failed to remove unused temp file", filePath)
		}

		apiV1Server500Error(w, r) // bad request
		return
	}

	ai := AiDecodeIncome{}
	ai.decodeUploadToPayIn(ul.Upload)

	apiV1SendJson(ai, w, r, ss)
}

func saveUploadsMetaToDB(id int64, filePath string,
	r *http.Request, ss *loan.Session) (ulMeta loan.Uploads, duplicate bool, e error) {
	duplicate = false
	e = r.ParseMultipartForm(10 << 20) // we should have ready parsed this, just in case
	if e != nil {
		return
	}
	file, header, e := r.FormFile("files")

	file.Seek(0, 0) //seek to beginning
	checksum := sha256File(file)
	ulMeta.Id = id
	ulMeta.Ts = time.Now()
	ulMeta.FileName = header.Filename
	file.Seek(0, 0) //seek to beginning
	ulMeta.Format = header.Header.Get("Content-type")
	ulMeta.Size = header.Size // necessary to prevent duplicate
	ulMeta.LastModified = 0
	ulMeta.Sha256 = checksum // necessary to prevent duplicate
	ulMeta.By = ss.User
	e = ulMeta.Write() // this Id will have the real Id if there is duplicates

	if e != nil {
		log.Error("Fail to update db ", ulMeta, e)
	} else {
		if (id > 0 && ulMeta.Id != id) || (id == 0 && ulMeta.IsDuplicate) {
			duplicate = true
		}
		ul := uploadsOnDisk{}
		ul.Upload = ulMeta
		e = os.Rename(filePath, ul.filePath())
		if e != nil {
			os.Remove(filePath)
			log.Error("fail to move file from ", filePath, "to", ul.filePath())
		}
	}
	return
}

func saveUploadToFile(r *http.Request) (filename string, e error) {
	e = r.ParseMultipartForm(10 << 20)
	if e != nil {
		return
	}
	file, header, e := r.FormFile("files")
	if e != nil {
		log.Println("Error Getting File", e)
		return
	}

	out, pathError := ioutil.TempFile(config.UploadsDir.FileDir, "can-del-upload-*.tmp")
	if pathError != nil {
		log.Println("Error Creating a file for writing", pathError)
		return
	}

	out.Seek(0, 0) //seek to beginning
	size, e := io.Copy(out, file)
	if e != nil {
		os.Remove(out.Name()) //remove on failure
		log.Println("Error copying", e)
		return
	}

	if size != header.Size {
		e = errors.New("written file with incorrect size")
	}
	return out.Name(), e
}

func getRequestedUpload(w http.ResponseWriter, r *http.Request, ss *loan.Session) (ret uploadsOnDisk, e error) {
	strId := r.URL.Path[len(apiV1Prefix+"upload-as-image/"):] //remove prefix
	Id, e := strconv.Atoi(strId)
	if e != nil {
		log.Error("Invalid uploads Id cannot convert to integer", Id, e)
		apiV1Client403Error(w, r, ss)
		return
	}

	ul := loan.Uploads{}
	e = ul.Read(int64(Id))
	if e != nil {
		log.Error("Upload not found or read error from db", Id, e)
		apiV1Client404Error(w, r, ss)
		return
	}

	ret.Upload = ul
	return
}

func apiV1UploadAsImage(w http.ResponseWriter, r *http.Request, ss *loan.Session) {
	ul, e := getRequestedUpload(w, r, ss)
	if e != nil {
		return
	}

	// if this is image itself, serve it directly
	if strings.Contains(strings.ToLower(ul.Upload.Format), "image") {
		f, e := os.Open(ul.filePath())
		if e == nil {
			defer f.Close()
			fi, e := f.Stat()
			if e == nil {
				w.Header().Set("Content-Disposition", "attachment; filename="+ul.Upload.FileName)
				http.ServeContent(w, r, ul.filePath(), fi.ModTime(), f)
				return
			}
		}
		// if we reach here, some err has happened
		log.Error("failed to serve image file ", ul, e)
		apiV1Server500Error(w, r)
		return
	}

	// see if a converted image exist, if not convert it and then send
	if !fileExists(ul.jpgPath()) {
		e = ul.convertUploadsToJpg()
		if e != nil {
			// serve a default no preview is available
			http.ServeFile(w, r, config.UploadsDir.JpgDefault)
			log.Error("error creating preview image", ul, e)
			return
		}
	}
	if fileExists(ul.jpgPath()) {
		http.ServeFile(w, r, ul.jpgPath())
		return
	} else {
		apiV1Client404Error(w, r, ss)
	}

}
func apiV1UploadAsThumbnail(w http.ResponseWriter, r *http.Request, ss *loan.Session) {
	ul, e := getRequestedUpload(w, r, ss)
	if e != nil {
		return
	}

	// see if a thumbnail is available already
	if !fileExists(ul.thumbPath()) {
		e = ul.convertUploadsToThumb()
		if e != nil {
			// serve a default no preview is available
			http.ServeFile(w, r, config.UploadsDir.ThumbDefault)
			log.Error("error creating preview image", ul, e)
			return
		}
	}
	if fileExists(ul.thumbPath()) {
		http.ServeFile(w, r, ul.thumbPath())
		return
	} else {
		apiV1Client404Error(w, r, ss)
	}
}

func apiV1UploadAPDF(w http.ResponseWriter, r *http.Request, ss *loan.Session) {
	ul, e := getRequestedUpload(w, r, ss)
	if e != nil {
		return
	}

	//get file type
	fileType, e := ul.GetFileType()
	if e != nil {
		apiV1Client403Error(w, r, ss)
		return
	}

	// if its ready pdf, no need to convert
	if fileType == "pdf" {
		f, e := os.Open(ul.filePath())
		if e == nil {
			defer f.Close()
			fi, e := f.Stat()
			if e == nil {
				w.Header().Set("Content-Disposition", "attachment; filename="+ul.Upload.FileName)
				http.ServeContent(w, r, ul.filePath(), fi.ModTime(), f)
				return
			}
		}
		// if we reach here, some err has happened
		log.Error("failed to serve pdf file ", ul, e)
		apiV1Server500Error(w, r)
		return
	}

	// see if a converted pdf exist, if not convert it and then send
	if !fileExists(ul.pdfPath()) {
		e = ul.convertUploadsToPDF()
		if e != nil {
			// serve a default no preview is available
			http.ServeFile(w, r, config.UploadsDir.PdfDefault)
			log.Error("error creating preview image", ul, e)
			return
		}
	}
	if fileExists(ul.pdfPath()) {
		http.ServeFile(w, r, ul.pdfPath())
		return
	} else {
		apiV1Client404Error(w, r, ss)
	}
}