Merge pull request awsdocs#1658 from Laren-AWS/Laren-AWS/s3-presignedurl

S3 presigned URL example with Requests package.

python/example_code/s3/.metadata.yaml

@@ -10,6 +10,9 @@ files:
   - path: s3_basics/object_wrapper.py
     services:
       - s3
+  - path: s3_basics/presigned_url.py
+    services:
+      - s3
   - path: s3_basics/test/conftest.py
     services:
       - s3
@@ -22,6 +25,9 @@ files:
   - path: s3_basics/test/test_object_wrapper.py
     services:
       - s3
+  - path: s3_basics/test/test_presigned_url.py
+    services:
+      - s3
 ...
 ---
 # Amazon S3 file transfer demo

python/example_code/s3/s3_basics/ReadMe.md

@@ -13,6 +13,7 @@ Learn to create, get, remove, and configure buckets and objects.
   Credentials Reference Guide](https://docs.aws.amazon.com/credref/latest/refdocs/creds-config-files.html).
 - Python 3.7 or later
 - Boto 3 1.11.10 or later
+- Requests 2.24.0 or later
 - PyTest 5.3.5 or later (to run unit tests)
 
 ## Cautions
@@ -30,28 +31,27 @@ Learn to create, get, remove, and configure buckets and objects.
 
 ## Running the code
 
-Both `bucket_wrapper.py` and `object_wrapper.py` contain `usage_demo` functions
-that demonstrate ways to use the functions in their respective modules. 
-For example, to see the bucket demonstration, run the module in a command window.
+**bucket_wrapper.py** and **object_wrapper.py**
+
+These scripts contain `usage_demo` functions that demonstrate ways to use the 
+functions in their respective modules. For example, to see the bucket demonstration, 
+run the module in a command window.
 
 ```
 python -m bucket_wrapper
 ``` 
 
-You can also run individual functions in the Python shell to make requests to your 
-AWS account. For example, run the following commands to create a bucket, upload 
-an object, get the object, empty the bucket, and delete the bucket.  
-
-    > python
-    >>> import time
-    >>> bucket_name = f"bucket{time.time_ns()}"
-    >>> import bucket_wrapper
-    >>> bucket = bucket_wrapper.create_bucket(bucket_name, region='us-west-2')
-    >>> import object_wrapper
-    >>> object_wrapper.put_object(bucket, 'my-test-object', b'My test data')
-    >>> obj = object_wrapper.get_object(bucket, 'my-test-object')
-    >>> object_wrapper.empty_bucket(bucket)
-    >>> bucket_wrapper.delete_bucket(bucket)
+**presigned_url.py**
+
+This script generates a presigned URL and uses the Requests package to get or 
+put a file in an Amazon S3 bucket. For example, run the following command to get
+a file from Amazon S3 at a command prompt.
+
+```
+python -m presigned_url.py your-bucket-name your-object-key get
+``` 
+
+Run the script with the `-h` flag to get more help.
 
 ## Running the tests
 

python/example_code/s3/s3_basics/bucket_wrapper.py

@@ -405,37 +405,6 @@ def generate_presigned_post(bucket_name, object_key, expires_in):
     return response
 
 
-def generate_presigned_url(bucket_name, client_method, method_parameters,
-                           expires_in):
-    """
-    Generate a presigned Amazon S3 URL that can be used to perform an action on
-    a bucket. A presigned URL can be used for a limited time to let someone without
-    an AWS account perform an action.
-
-    Usage is shown in usage_demo at the end of this module.
-
-    :param bucket_name: The name of the bucket on which the action can be performed.
-    :param client_method: The name of the client method that the URL performs.
-    :param method_parameters: The parameters of the specified client method.
-    :param expires_in: The number of seconds the presigned URL is valid for.
-    :return: The presigned URL.
-    """
-    s3 = get_s3()
-    try:
-        url = s3.meta.client.generate_presigned_url(
-            ClientMethod=client_method,
-            Params=method_parameters,
-            ExpiresIn=expires_in
-        )
-        logger.info("Got presigned URL: %s", url)
-    except ClientError:
-        logger.exception("Couldn't get a presigned URL for bucket '%s' "
-                         "and client method '%s'.",
-                         bucket_name, client_method)
-        raise
-    return url
-
-
 def usage_demo():
     """Demonstrates ways to use the functions in this module."""
     prefix = 'usage-demo-bucket-wrapper-'
@@ -518,15 +487,6 @@ def usage_demo():
     print(f"Bucket {bucket.name} has lifecycle configuration {json.dumps(get_rules)}.")
     delete_lifecycle_configuration(bucket.name)
 
-    url = generate_presigned_url(
-        bucket.name,
-        'list_objects',
-        {'Bucket': bucket.name},
-        10
-    )
-    print(f"Generated a pre-signed URL that can be used to list the objects in "
-          f"bucket {bucket.name}. The URL is {url}.")
-
     for bucket in created_buckets:
         bucket.delete()
         print(f"Deleted bucket {bucket.name}.")

python/example_code/s3/s3_basics/presigned_url.py

@@ -0,0 +1,83 @@
+# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+"""
+Purpose
+
+Shows how to use the AWS SDK for Python (Boto3) with Amazon Simple Storage Service
+(Amazon S3) to generate a presigned URL that can perform an action for a limited
+time with your credentials. Also shows how to use the Requests package
+to make a request with the URL.
+"""
+
+import argparse
+import logging
+import boto3
+from botocore.exceptions import ClientError
+import requests
+
+logger = logging.getLogger(__name__)
+
+
+def generate_presigned_url(s3_client, client_method, method_parameters, expires_in):
+    """
+    Generate a presigned Amazon S3 URL that can be used to perform an action.
+
+    :param s3_client: A Boto3 Amazon S3 client.
+    :param client_method: The name of the client method that the URL performs.
+    :param method_parameters: The parameters of the specified client method.
+    :param expires_in: The number of seconds the presigned URL is valid for.
+    :return: The presigned URL.
+    """
+    try:
+        url = s3_client.generate_presigned_url(
+            ClientMethod=client_method,
+            Params=method_parameters,
+            ExpiresIn=expires_in
+        )
+        logger.info("Got presigned URL: %s", url)
+    except ClientError:
+        logger.exception(
+            "Couldn't get a presigned URL for client method '%s'.", client_method)
+        raise
+    return url
+
+
+def usage_demo():
+    logging.basicConfig(level=logging.INFO, format='%(levelname)s: %(message)s')
+
+    print('-'*88)
+    print("Welcome to the Amazon S3 presigned URL demo.")
+    print('-'*88)
+
+    parser = argparse.ArgumentParser()
+    parser.add_argument('bucket', help="The name of the bucket.")
+    parser.add_argument('key', help="The key of the object.")
+    parser.add_argument(
+        'action', choices=('get', 'put'), help="The action to perform.")
+    args = parser.parse_args()
+
+    s3_client = boto3.client('s3')
+    client_action = 'get_object' if args.action == 'get' else 'put_object'
+    url = generate_presigned_url(
+        s3_client, client_action, {'Bucket': args.bucket, 'Key': args.key}, 1000)
+
+    print("Using the Requests package to send a request to the URL.")
+    response = None
+    if args.action == 'get':
+        response = requests.get(url)
+    elif args.action == 'put':
+        print("Putting data to the URL.")
+        with open(args.key, 'r') as object_file:
+            object_text = object_file.read()
+        response = requests.put(url, data=object_text)
+
+    print("Got response:")
+    print(f"Status: {response.status_code}")
+    print(response.text)
+
+    print('-'*88)
+
+
+if __name__ == '__main__':
+    usage_demo()

python/example_code/s3/s3_basics/test/test_bucket_wrapper.py

@@ -343,20 +343,3 @@ def test_generate_presigned_post(make_unique_name):
     segments = urlparse(response['url'])
     assert all([segments.scheme, segments.netloc, segments.path])
     assert response['fields']['key'] == object_key
-
-
-@pytest.mark.parametrize('client_method,method_parameters', [
-    ('list_objects', {'Bucket': 'test-bucket'}),
-    ('put_object', {'Bucket': 'test-bucket', 'Key': 'test-object'})
-])
-def test_generate_presigned_url(make_unique_name, client_method,
-                                method_parameters):
-    """"Test that generating a presigned URL works as expected."""
-    bucket_name = make_unique_name('bucket')
-    expires_in = 60
-
-    url = bucket_wrapper.generate_presigned_url(
-        bucket_name, client_method, method_parameters, expires_in
-    )
-    segments = urlparse(url)
-    assert all([segments.scheme, segments.netloc, segments.path])

python/example_code/s3/s3_basics/test/test_presigned_url.py

@@ -0,0 +1,22 @@
+# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+"""
+Unit tests for presigned_url.py functions.
+"""
+
+import boto3
+
+import presigned_url
+
+
+def test_generate_presigned_url():
+    s3_client = boto3.client('s3')
+    client_method = 'get_object'
+    method_params = {'Bucket': 'test-bucket', 'Key': 'test-key'}
+    expires = 10
+
+    got_url = presigned_url.generate_presigned_url(
+        s3_client, client_method, method_params, expires)
+    assert 'test-bucket' in got_url
+    assert 'test-key' in got_url