Merge pull request awsdocs#1556 from awsdocs/doug-s3-presign-tag

Added new Go v2 code example to get pre-signed URL for S3 object

gov2/s3/GeneratePresignedURL/GeneratePresignedURLv2.go

@@ -0,0 +1,78 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX - License - Identifier: Apache - 2.0
+// snippet-start:[s3.go-v2.generate_presigned_url]
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+
+	v4 "github.com/aws/aws-sdk-go-v2/aws/signer/v4"
+	"github.com/aws/aws-sdk-go-v2/config"
+	"github.com/aws/aws-sdk-go-v2/service/s3"
+)
+
+// S3PresignGetObjectAPI defines the interface for the PresignGetObject function.
+// We use this interface to test the function using a mocked service.
+type S3PresignGetObjectAPI interface {
+	PresignGetObject(
+		ctx context.Context,
+		params *s3.GetObjectInput,
+		optFns ...func(*s3.PresignOptions)) (*v4.PresignedHTTPRequest, error)
+}
+
+// GetPresignedURL retrieves a presigned URL for an Amazon S3 bucket object.
+// Inputs:
+//     c is the context of the method call, which includes the AWS Region.
+//     api is the interface that defines the method call.
+//     input defines the input arguments to the service call.
+// Output:
+//     If successful, the presigned URL for the object and nil.
+//     Otherwise, nil and an error from the call to PresignGetObject.
+func GetPresignedURL(c context.Context, api S3PresignGetObjectAPI, input *s3.GetObjectInput) (*v4.PresignedHTTPRequest, error) {
+	resp, err := api.PresignGetObject(c, input)
+	if err != nil {
+		return nil, err
+	}
+
+	return resp, nil
+}
+
+func main() {
+	bucket := flag.String("b", "", "The bucket")
+	key := flag.String("k", "", "The object key")
+
+	flag.Parse()
+
+	if *bucket == "" || *key == "" {
+		fmt.Println("You must supply a bucket name (-b BUCKET) and object key (-k KEY)")
+		return
+	}
+
+	cfg, err := config.LoadDefaultConfig(context.TODO())
+	if err != nil {
+		panic("configuration error, " + err.Error())
+	}
+
+	client := s3.NewFromConfig(cfg)
+
+	input := &s3.GetObjectInput{
+		Bucket: bucket,
+		Key:    key,
+	}
+
+	psClient := s3.NewPresignClient(client)
+
+	resp, err := GetPresignedURL(context.Background(), psClient, input)
+	if err != nil {
+		fmt.Println("Got an error retrieving pre-signed object:")
+		fmt.Println(err)
+		return
+	}
+
+	fmt.Println("The URL: ")
+	fmt.Println(resp.URL)
+}
+
+// snippet-end:[s3.go-v2.generate_presigned_url]

gov2/s3/GeneratePresignedURL/GeneratePresignedURLv2_test.go

@@ -0,0 +1,107 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"io/ioutil"
+	"testing"
+	"time"
+
+	v4 "github.com/aws/aws-sdk-go-v2/aws/signer/v4"
+	"github.com/aws/aws-sdk-go-v2/config"
+	"github.com/aws/aws-sdk-go-v2/service/s3"
+)
+
+type S3PresignGetObjectImpl struct{}
+
+func (dt S3PresignGetObjectImpl) PresignGetObject(
+	ctx context.Context,
+	params *s3.GetObjectInput,
+	optFns ...func(*s3.PresignOptions)) (*v4.PresignedHTTPRequest, error) {
+
+	// Get the region:
+	cfg, err := config.LoadDefaultConfig(context.TODO())
+	if err != nil {
+		panic("configuration error, " + err.Error())
+	}
+
+	region := cfg.Region
+
+	string64 := "1234567890123456789012345678901234567890123456789012345678901234"
+
+	url := "https://" +
+		*params.Bucket +
+		".s3." + region +
+		".amazonaws.com/" +
+		*params.Key +
+		"?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=CREDENTIALS" +
+		region +
+		"%2Fs3%2Faws4_request&X-Amz-Date=20210104T220556Z&X-Amz-Expires=900&X-Amz-SignedHeaders=host&x-id=GetObject&X-Amz-Signature=" + string64
+
+	output := &v4.PresignedHTTPRequest{
+		URL: url,
+	}
+
+	return output, nil
+}
+
+type Config struct {
+	Bucket string `json:"Bucket"`
+	Key    string `json:"Key"`
+}
+
+var configFileName = "config.json"
+
+var globalConfig Config
+
+func populateConfiguration() error {
+	content, err := ioutil.ReadFile(configFileName)
+	if err != nil {
+		return err
+	}
+
+	text := string(content)
+
+	err = json.Unmarshal([]byte(text), &globalConfig)
+	if err != nil {
+		return err
+	}
+
+	if globalConfig.Bucket == "" || globalConfig.Key == "" {
+		msg := "You must supply a value for Bucket and Key in " + configFileName
+		return errors.New(msg)
+	}
+
+	return nil
+}
+
+func TestPresignGetObject(t *testing.T) {
+	thisTime := time.Now()
+	nowString := thisTime.Format("2006-01-02 15:04:05 Monday")
+	t.Log("Starting unit test at " + nowString)
+
+	err := populateConfiguration()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	api := &S3PresignGetObjectImpl{}
+
+	input := &s3.GetObjectInput{
+		Bucket: &globalConfig.Bucket,
+		Key:    &globalConfig.Key,
+	}
+
+	resp, err := GetPresignedURL(context.Background(), *api, input)
+	if err != nil {
+		t.Log("Got an error ...:")
+		t.Log(err)
+		return
+	}
+
+	t.Log("URL:")
+	t.Log(resp.URL)
+}

gov2/s3/GeneratePresignedURL/README.md

@@ -0,0 +1,10 @@
+### GeneratePresignedURLv2.go
+
+This example retrieves a presigned URL for an Amazon Simple Storage Service (Amazon S3) bucket object.
+
+`go run GeneratePresignedURLv2.go -b BUCKET -k KEY`
+
+- _BUCKET_ is the name of the bucket.
+- _KEY_ is the name of the object (key).
+
+The unit test accepts a similar value in _config.json_.

gov2/s3/GeneratePresignedURL/config.json

@@ -0,0 +1,4 @@
+{
+    "Bucket": "aws-docs-example-bucket",
+    "Key": "aws-docs-example-key"
+}

gov2/s3/GeneratePresignedURL/go.mod

@@ -0,0 +1,9 @@
+module mymain
+
+go 1.15
+
+require (
+	github.com/aws/aws-sdk-go-v2 v0.31.0
+	github.com/aws/aws-sdk-go-v2/config v0.4.0
+	github.com/aws/aws-sdk-go-v2/service/s3 v0.31.0
+)

gov2/s3/GeneratePresignedURL/go.sum

@@ -0,0 +1,31 @@
+github.com/aws/aws-sdk-go-v2 v0.31.0 h1:TNTDsz+Xq80nYzZPUFS4a2Oyjz9jKHKcTuNAXtcW8b8=
+github.com/aws/aws-sdk-go-v2 v0.31.0/go.mod h1:IQw4KL7QIoaNDT3WoEBV1fDlVRhp/WTRteoaplV3SHo=
+github.com/aws/aws-sdk-go-v2/config v0.4.0 h1:16lwnZRhleaPbDesZgEJbHxuOv4wy12A372mkhmiktc=
+github.com/aws/aws-sdk-go-v2/config v0.4.0/go.mod h1:5uxQPUBCF+TwwWYo2xau4N+rSOS47ZH+QvLbae1Cckc=
+github.com/aws/aws-sdk-go-v2/credentials v0.2.0 h1:YDv/0/8BzaZtpS4jfptcyIPh5zlhmIhbM2RtNscn/bo=
+github.com/aws/aws-sdk-go-v2/credentials v0.2.0/go.mod h1:U81m6Xb5IpJ66ZnotiG7/6JJFuwrc8q8rWpXQxYP0hI=
+github.com/aws/aws-sdk-go-v2/feature/ec2/imds v0.1.0 h1:zwhJDxNht/+a0QGy3RCveUFf6REXcmaQIHcYS11m5KY=
+github.com/aws/aws-sdk-go-v2/feature/ec2/imds v0.1.0/go.mod h1:d3o/QBgbYw2OYmbv/EGYs0zFH47qsCKCTDbaOgdQGH8=
+github.com/aws/aws-sdk-go-v2/service/internal/accept-encoding v0.4.0 h1:osjGuGbk/aVW8u2yhOijPhxLU1ardwPDsga5HHyQMbw=
+github.com/aws/aws-sdk-go-v2/service/internal/accept-encoding v0.4.0/go.mod h1:Pjv1Z+nRaluwWCMuB6OQeqGRyiGk2WTrKG8RHs5wZug=
+github.com/aws/aws-sdk-go-v2/service/internal/presigned-url v0.2.0 h1:xeqwfWQGg3hjLMs61PlixdxhU+qqrd7S50j/3kV1j/0=
+github.com/aws/aws-sdk-go-v2/service/internal/presigned-url v0.2.0/go.mod h1:Ef71w/O9Ulhxj8gD9Pq2S0lXMvyNzFLMRuIxWpDRQxk=
+github.com/aws/aws-sdk-go-v2/service/internal/s3shared v0.4.0 h1:OiRO8lneLP7wJ80dqAwHpIRcMInUO04HzcQUVtPwk3U=
+github.com/aws/aws-sdk-go-v2/service/internal/s3shared v0.4.0/go.mod h1:fMsE4Rr6OkxQUmZxi4Amj8LS0BakLZw05Rog0jYStQM=
+github.com/aws/aws-sdk-go-v2/service/s3 v0.31.0 h1:KDBpodyszhL8F83QYv36qBzDj99oPlt1coZNGSFKTXU=
+github.com/aws/aws-sdk-go-v2/service/s3 v0.31.0/go.mod h1:KnvsmhsdHaJJZatMeNscBKaEmz0V5oXe1N5ZaLmGDBs=
+github.com/aws/aws-sdk-go-v2/service/sts v0.31.0 h1:iJwlIyswoW4VM8RUmhC3397jdGa6QhMUtUf5daX+/a0=
+github.com/aws/aws-sdk-go-v2/service/sts v0.31.0/go.mod h1:gliVu4/DZsKINvBoEcMIlxMIQft/yPYQhnSLxwiWqFM=
+github.com/aws/smithy-go v0.5.0 h1:ArsdWUrb1n6/V/REXhuwq2TZv+kuqOBpMlGBd2EkDYM=
+github.com/aws/smithy-go v0.5.0/go.mod h1:EzMw8dbp/YJL4A5/sbhGddag+NPT7q084agLbB9LgIw=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/google/go-cmp v0.4.1/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/google/go-cmp v0.5.4 h1:L8R9j+yAqZuZjsqh/z+F1NCffTKKLShY6zXTItVIZ8M=
+github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/jmespath/go-jmespath v0.4.0/go.mod h1:T8mJZnbsbmF+m6zOOFylbeCJqk5+pHWvzYPziyZiYoo=
+github.com/jmespath/go-jmespath/internal/testify v1.5.1/go.mod h1:L3OGu8Wl2/fWfCI6z80xFu9LTZmf1ZRjMHUOPmWr69U=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=

gov2/s3/README.md

@@ -57,6 +57,17 @@ This example deletes an Amazon S3 bucket object.
 
 The unit test accepts similar values in _config.json_.
 
+### GeneratePresignedURL/GeneratePresignedURLv2.go
+
+This example retrieves a presigned URL for an Amazon S3 bucket object.
+
+`go run GeneratePresignedURLv2.go -b BUCKET -k KEY`
+
+- _BUCKET_ is the name of the bucket.
+- _KEY_ is the name of the object (key).
+
+The unit test accepts a similar value in _config.json_.
+
 ### GetBucketAcl/GetBucketAclv2.go
 
 This example retrieves the access control list (ACL) for an Amazon S3 bucket.

gov2/s3/metadata.yaml

@@ -23,6 +23,12 @@ files:
   - path: DeleteObject/DeleteObjectv2_test.go
     services:
       - s3
+  - path: GeneratePresignedURL/GeneratePresignedURLv2.go
+    services:
+      - s3
+  - path: GeneratePresignedURL/GeneratePresignedURLv2_test.go
+    services:
+      - s3
   - path: GetBucketAcl/GetBucketAclv2.go
     services:
       - s3