init

simples3.go

@@ -0,0 +1,198 @@
+// LICENSE MIT
+// Copyright (c) 2018, Rohan Verma <hello@rohanverma.net>
+
+package simples3
+
+import (
+	"bytes"
+	"crypto/hmac"
+	"crypto/sha256"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"mime/multipart"
+	"net/http"
+	"net/http/httputil"
+	"time"
+)
+
+// S3 provides a wrapper around your S3 credentials.
+type S3 struct {
+	AccessKey string
+	SecretKey string
+	Region    string
+
+	URIFormat string
+}
+
+type UploadInput struct {
+	Bucket      string
+	ObjectKey   string
+	FileName    string
+	ContentType string
+	Body        multipart.File
+}
+
+type DeleteInput struct {
+	Bucket    string
+	ObjectKey string
+}
+
+func New(region, accessKey, secretKey string) *S3 {
+	return &S3{
+		Region:    region,
+		AccessKey: accessKey,
+		SecretKey: secretKey,
+
+		URIFormat: "https://s3.%s.amazonaws.com/%s",
+	}
+}
+
+func detectFileSize(body multipart.File) int64 {
+	switch r := body.(type) {
+	case io.Seeker:
+		pos, _ := r.Seek(0, 1)
+		defer r.Seek(pos, 0)
+
+		n, err := r.Seek(0, 2)
+		if err != nil {
+			return -1
+		}
+		return n
+	}
+	return -1
+}
+
+func (s3 *S3) FileUpload(u UploadInput) error {
+	policies, err := s3.CreateUploadPolicies(UploadConfig{
+		UploadURL:   fmt.Sprintf(s3.URIFormat, s3.Region, u.Bucket),
+		BucketName:  u.Bucket,
+		ObjectKey:   u.ObjectKey,
+		ContentType: u.ContentType,
+		FileSize:    detectFileSize(u.Body),
+		MetaData: map[string]string{
+			"success_action_status": "200",
+		},
+	})
+
+	if err != nil {
+		return err
+	}
+
+	var b bytes.Buffer
+	w := multipart.NewWriter(&b)
+
+	for k, v := range policies.Form {
+		log.Println(k, v)
+		if err := w.WriteField(k, v); err != nil {
+			return err
+		}
+	}
+
+	fw, err := w.CreateFormFile("file", u.FileName)
+	if err != nil {
+		return err
+	}
+	if _, err = io.Copy(fw, u.Body); err != nil {
+		return err
+	}
+
+	// Don't forget to close the multipart writer.
+	// If you don't close it, your request will be missing the terminating boundary.
+	if err := w.Close(); err != nil {
+		return err
+	}
+
+	// Now that you have a form, you can submit it to your handler.
+	req, err := http.NewRequest("POST", policies.URL, &b)
+	if err != nil {
+		return err
+	}
+	// Don't forget to set the content type, this will contain the boundary.
+	req.Header.Set("Content-Type", w.FormDataContentType())
+
+	// Submit the request
+	client := &http.Client{}
+	res, err := client.Do(req)
+	if err != nil {
+		return err
+	}
+
+	// Check the response
+	if res.Status != "200 OK" {
+		err = fmt.Errorf("status code: %s", res.Status)
+		data, _ := ioutil.ReadAll(res.Body)
+		log.Printf("response:%s\n", string(data))
+		return err
+	}
+
+	return nil
+}
+
+func (s3 *S3) FileDelete(u DeleteInput) error {
+	url := fmt.Sprintf(
+		s3.URIFormat+"/%s",
+		s3.Region, u.Bucket, u.ObjectKey,
+	)
+	log.Println(url)
+	req, err := http.NewRequest(
+		"DELETE", url, nil,
+	)
+	if err != nil {
+		return err
+	}
+
+	date := req.Header.Get("Date")
+	t := time.Now().UTC()
+	if date != "" {
+		var err error
+		t, err = time.Parse(http.TimeFormat, date)
+		if err != nil {
+			return err
+		}
+	}
+	req.Header.Set("Date", t.Format(amzDateISO8601TimeFormat))
+
+	// The x-amz-content-sha256 header is required for all AWS
+	// Signature Version 4 requests. It provides a hash of the
+	// request payload. If there is no payload, you must provide
+	// the hash of an empty string.
+	emptyhash := "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
+	req.Header.Set("x-amz-content-sha256", emptyhash)
+
+	k := s3.signKeys(t)
+	h := hmac.New(sha256.New, k)
+
+	s3.writeStringToSign(h, t, req)
+
+	auth := bytes.NewBufferString("AWS4-HMAC-SHA256 ")
+	auth.Write([]byte("Credential=" + s3.AccessKey + "/" + s3.creds(t)))
+	auth.Write([]byte{',', ' '})
+	auth.Write([]byte("SignedHeaders="))
+	writeHeaderList(auth, req)
+	auth.Write([]byte{',', ' '})
+	auth.Write([]byte("Signature=" + fmt.Sprintf("%x", h.Sum(nil))))
+
+	req.Header.Set("Authorization", auth.String())
+
+	dump, err := httputil.DumpRequest(req, true)
+	log.Printf("%q", dump)
+
+	// Submit the request
+	client := &http.Client{}
+	res, err := client.Do(req)
+	if err != nil {
+		return err
+	}
+
+	// // Check the response
+	if res.Status != "204 No Content" {
+		err = fmt.Errorf("status code: %s", res.Status)
+		data, _ := ioutil.ReadAll(res.Body)
+		log.Printf("response:%s\n", string(data))
+		return err
+	}
+
+	return nil
+}