撰寫 S3 Object Lambda 存取點的 Lambda 函數

package com.amazon.s3.objectlambda;

import com.amazonaws.services.lambda.runtime.Context;
import com.amazonaws.services.lambda.runtime.events.S3ObjectLambdaEvent;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3Client;
import com.amazonaws.services.s3.model.WriteGetObjectResponseRequest;

import java.io.ByteArrayInputStream;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;

public class Example1 {

    public void handleRequest(S3ObjectLambdaEvent event, Context context) throws Exception {
        AmazonS3 s3Client = AmazonS3Client.builder().build();

        // Check to see if the request contains all of the necessary information.
        // If it does not, send a 4XX response and a custom error code and message.
        // Otherwise, retrieve the object from S3 and stream it
        // to the client unchanged.
        var tokenIsNotPresent = !event.getUserRequest().getHeaders().containsKey("requiredToken");
        if (tokenIsNotPresent) {
            s3Client.writeGetObjectResponse(new WriteGetObjectResponseRequest()
                    .withRequestRoute(event.outputRoute())
                    .withRequestToken(event.outputToken())
                    .withStatusCode(403)
                    .withContentLength(0L).withInputStream(new ByteArrayInputStream(new byte[0]))
                    .withErrorCode("MissingRequiredToken")
                    .withErrorMessage("The required token was not present in the request."));
            return;
        }

        // Prepare the presigned URL for use and make the request to S3.
        HttpClient httpClient = HttpClient.newBuilder().build();
        var presignedResponse = httpClient.send(
                HttpRequest.newBuilder(new URI(event.inputS3Url())).GET().build(),
                HttpResponse.BodyHandlers.ofInputStream());

        // Stream the original bytes back to the caller.
        s3Client.writeGetObjectResponse(new WriteGetObjectResponseRequest()
                .withRequestRoute(event.outputRoute())
                .withRequestToken(event.outputToken())
                .withInputStream(presignedResponse.body()));
    }
}

import boto3
import requests 

def handler(event, context):
    s3 = boto3.client('s3')

    """
    Retrieve the operation context object from the event. This object indicates where the WriteGetObjectResponse request
    should be delivered and contains a presigned URL in 'inputS3Url' where we can download the requested object from.
    The 'userRequest' object has information related to the user who made this 'GetObject' request to 
    S3 Object Lambda.
    """
    get_context = event["getObjectContext"]
    user_request_headers = event["userRequest"]["headers"]

    route = get_context["outputRoute"]
    token = get_context["outputToken"]
    s3_url = get_context["inputS3Url"]

    # Check for the presence of a 'CustomHeader' header and deny or allow based on that header.
    is_token_present = "SuperSecretToken" in user_request_headers

    if is_token_present:
        # If the user presented our custom 'SuperSecretToken' header, we send the requested object back to the user.
        response = requests.get(s3_url)
        s3.write_get_object_response(RequestRoute=route, RequestToken=token, Body=response.content)
    else:
        # If the token is not present, we send an error back to the user. 
        s3.write_get_object_response(RequestRoute=route, RequestToken=token, StatusCode=403,
        ErrorCode="NoSuperSecretTokenFound", ErrorMessage="The request was not secret enough.")

    # Gracefully exit the Lambda function.
    return { 'status_code': 200 }

const { S3 } = require('aws-sdk');
const axios = require('axios').default;

exports.handler = async (event) => {
    const s3 = new S3();

    // Retrieve the operation context object from the event. This object indicates where the WriteGetObjectResponse request
    // should be delivered and contains a presigned URL in 'inputS3Url' where we can download the requested object from.
    // The 'userRequest' object has information related to the user who made this 'GetObject' request to S3 Object Lambda.
    const { userRequest, getObjectContext } = event;
    const { outputRoute, outputToken, inputS3Url } = getObjectContext;

    // Check for the presence of a 'CustomHeader' header and deny or allow based on that header.
    const isTokenPresent = Object
        .keys(userRequest.headers)
        .includes("SuperSecretToken");

    if (!isTokenPresent) {
        // If the token is not present, we send an error back to the user. The 'await' in front of the request
        // indicates that we want to wait for this request to finish sending before moving on. 
        await s3.writeGetObjectResponse({
            RequestRoute: outputRoute,
            RequestToken: outputToken,
            StatusCode: 403,
            ErrorCode: "NoSuperSecretTokenFound",
            ErrorMessage: "The request was not secret enough.",
        }).promise();
    } else {
        // If the user presented our custom 'SuperSecretToken' header, we send the requested object back to the user.
        // Again, note the presence of 'await'.
        const presignedResponse = await axios.get(inputS3Url);
        await s3.writeGetObjectResponse({
            RequestRoute: outputRoute,
            RequestToken: outputToken,
            Body: presignedResponse.data,
        }).promise();
    }

    // Gracefully exit the Lambda function.
    return { statusCode: 200 };
}

package com.amazon.s3.objectlambda;

import com.amazonaws.services.lambda.runtime.Context;
import com.amazonaws.services.lambda.runtime.events.S3ObjectLambdaEvent;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3Client;
import com.amazonaws.services.s3.model.WriteGetObjectResponseRequest;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.awt.Image;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;

public class Example2 {

    private static final int HEIGHT = 250;
    private static final int WIDTH = 250;

    public void handleRequest(S3ObjectLambdaEvent event, Context context) throws Exception {
        AmazonS3 s3Client = AmazonS3Client.builder().build();
        HttpClient httpClient = HttpClient.newBuilder().build();

        // Prepare the presigned URL for use and make the request to S3.
        var presignedResponse = httpClient.send(
                HttpRequest.newBuilder(new URI(event.inputS3Url())).GET().build(),
                HttpResponse.BodyHandlers.ofInputStream());

        // The entire image is loaded into memory here so that we can resize it.
        // Once the resizing is completed, we write the bytes into the body
        // of the WriteGetObjectResponse request.
        var originalImage = ImageIO.read(presignedResponse.body());
        var resizingImage = originalImage.getScaledInstance(WIDTH, HEIGHT, Image.SCALE_DEFAULT);
        var resizedImage = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
        resizedImage.createGraphics().drawImage(resizingImage, 0, 0, WIDTH, HEIGHT, null);

        var baos = new ByteArrayOutputStream();
        ImageIO.write(resizedImage, "png", baos);

        // Stream the bytes back to the caller.
        s3Client.writeGetObjectResponse(new WriteGetObjectResponseRequest()
                .withRequestRoute(event.outputRoute())
                .withRequestToken(event.outputToken())
                .withInputStream(new ByteArrayInputStream(baos.toByteArray())));
    }
}

import boto3
import requests 
import io
from PIL import Image

def handler(event, context):
    """
    Retrieve the operation context object from the event. This object indicates where the WriteGetObjectResponse request
    should be delivered and has a presigned URL in 'inputS3Url' where we can download the requested object from.
    The 'userRequest' object has information related to the user who made this 'GetObject' request to 
    S3 Object Lambda.
    """
    get_context = event["getObjectContext"]
    route = get_context["outputRoute"]
    token = get_context["outputToken"]
    s3_url = get_context["inputS3Url"]

    """
    In this case, we're resizing .png images that are stored in S3 and are accessible through the presigned URL
    'inputS3Url'.
    """
    image_request = requests.get(s3_url)
    image = Image.open(io.BytesIO(image_request.content))
    image.thumbnail((256,256), Image.ANTIALIAS)

    transformed = io.BytesIO()
    image.save(transformed, "png")

    # Send the resized image back to the client.
    s3 = boto3.client('s3')
    s3.write_get_object_response(Body=transformed.getvalue(), RequestRoute=route, RequestToken=token)

    # Gracefully exit the Lambda function.
    return { 'status_code': 200 }

const { S3 } = require('aws-sdk');
const axios = require('axios').default;
const sharp = require('sharp');

exports.handler = async (event) => {
    const s3 = new S3();

    // Retrieve the operation context object from the event. This object indicates where the WriteGetObjectResponse request
    // should be delivered and has a presigned URL in 'inputS3Url' where we can download the requested object from.
    const { getObjectContext } = event;
    const { outputRoute, outputToken, inputS3Url } = getObjectContext;

    // In this case, we're resizing .png images that are stored in S3 and are accessible through the presigned URL
    // 'inputS3Url'.
    const { data } = await axios.get(inputS3Url, { responseType: 'arraybuffer' });

    // Resize the image.
    const resized = await sharp(data)
        .resize({ width: 256, height: 256 })
        .toBuffer();

    // Send the resized image back to the client.
    await s3.writeGetObjectResponse({
        RequestRoute: outputRoute,
        RequestToken: outputToken,
        Body: resized,
    }).promise();

    // Gracefully exit the Lambda function.
    return { statusCode: 200 };
}

package com.amazon.s3.objectlambda;

import com.amazonaws.services.lambda.runtime.events.S3ObjectLambdaEvent;
import com.amazonaws.services.lambda.runtime.Context;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3Client;
import com.amazonaws.services.s3.model.WriteGetObjectResponseRequest;

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;

public class Example3 {

    public void handleRequest(S3ObjectLambdaEvent event, Context context) throws Exception {
        AmazonS3 s3Client = AmazonS3Client.builder().build();
        HttpClient httpClient = HttpClient.newBuilder().build();

        // Request the original object from S3.
        var presignedResponse = httpClient.send(
                HttpRequest.newBuilder(new URI(event.inputS3Url())).GET().build(),
                HttpResponse.BodyHandlers.ofInputStream());

        // Consume the incoming response body from the presigned request,
        // apply our transformation on that data, and emit the transformed bytes
        // into the body of the WriteGetObjectResponse request as soon as they're ready.
        // This example compresses the data from S3, but any processing pertinent
        // to your application can be performed here.
        var bodyStream = new GZIPCompressingInputStream(presignedResponse.body());

        // Stream the bytes back to the caller.
        s3Client.writeGetObjectResponse(new WriteGetObjectResponseRequest()
                .withRequestRoute(event.outputRoute())
                .withRequestToken(event.outputToken())
                .withInputStream(bodyStream));
    }

}

import boto3
import requests
import zlib
from botocore.config import Config


"""
A helper class to work with content iterators. Takes an interator and compresses the bytes that come from it. It
implements 'read' and '__iter__' so that the SDK can stream the response. 
"""
class Compress:
    def __init__(self, content_iter):
        self.content = content_iter
        self.compressed_obj = zlib.compressobj()

    def read(self, _size):
        for data in self.__iter__()
            return data

    def __iter__(self):
        while True:
            data = next(self.content)
            chunk = self.compressed_obj.compress(data)
            if not chunk:
                break

            yield chunk

        yield self.compressed_obj.flush()


def handler(event, context):
    """
    Setting the 'payload_signing_enabled' property to False allows us to send a streamed response back to the client.
    in this scenario, a streamed response means that the bytes are not buffered into memory as we're compressing them,
    but instead are sent straight to the user.
    """
    my_config = Config(
        region_name='eu-west-1',
        signature_version='s3v4',
        s3={
            "payload_signing_enabled": False
        }
    )
    s3 = boto3.client('s3', config=my_config)

    """
    Retrieve the operation context object from the event. This object indicates where the WriteGetObjectResponse request
    should be delivered and has a presigned URL in 'inputS3Url' where we can download the requested object from.
    The 'userRequest' object has information related to the user who made this 'GetObject' request to S3 Object Lambda.
    """
    get_context = event["getObjectContext"]
    route = get_context["outputRoute"]
    token = get_context["outputToken"]
    s3_url = get_context["inputS3Url"]

    # Compress the 'get' request stream.
    with requests.get(s3_url, stream=True) as r:
        compressed = Compress(r.iter_content())

        # Send the stream back to the client.
        s3.write_get_object_response(Body=compressed, RequestRoute=route, RequestToken=token, ContentType="text/plain",
                                     ContentEncoding="gzip")

    # Gracefully exit the Lambda function.
    return {'status_code': 200}

const { S3 } = require('aws-sdk');
const axios = require('axios').default;
const zlib = require('zlib');

exports.handler = async (event) => {
    const s3 = new S3();

    // Retrieve the operation context object from the event. This object indicates where the WriteGetObjectResponse request
    // should be delivered and has a presigned URL in 'inputS3Url' where we can download the requested object from.
    const { getObjectContext } = event;
    const { outputRoute, outputToken, inputS3Url } = getObjectContext;

    // Download the object from S3 and process it as a stream, because it might be a huge object and we don't want to
    // buffer it in memory. Note the use of 'await' because we want to wait for 'writeGetObjectResponse' to finish 
    // before we can exit the Lambda function. 
    await axios({
        method: 'GET',
        url: inputS3Url,
        responseType: 'stream',
    }).then(
        // Gzip the stream.
        response => response.data.pipe(zlib.createGzip())
    ).then(
        // Finally send the gzip-ed stream back to the client.
        stream => s3.writeGetObjectResponse({
            RequestRoute: outputRoute,
            RequestToken: outputToken,
            Body: stream,
            ContentType: "text/plain",
            ContentEncoding: "gzip",
        }).promise()
    );

    // Gracefully exit the Lambda function.
    return { statusCode: 200 };
}

import requests

def lambda_handler(event, context):
    print(event)
    
    # Extract the presigned URL from the input.
    s3_url = event["headObjectContext"]["inputS3Url"]

    # Get the head of the object from S3.     
    response = requests.head(s3_url)
    
    # Return the error to S3 Object Lambda (if applicable).           
    if (response.status_code >= 400):
        return {
            "statusCode": response.status_code,
            "errorCode": "RequestFailure",                         
            "errorMessage": "Request to S3 failed"    
    }
    
    # Store the headers in a dictionary.
    response_headers = dict(response.headers)

    # This obscures Content-Type in a transformation, it is optional to add
    response_headers["Content-Type"] = "" 

    # Return the headers to S3 Object Lambda.     
    return {
        "statusCode": response.status_code,
        "headers": response_headers     
        }

import requests 
import xmltodict

def lambda_handler(event, context):
    # Extract the presigned URL from the input.
    s3_url = event["listObjectsContext"]["inputS3Url"]


    # Get the head of the object from Amazon S3.
    response = requests.get(s3_url)

    # Return the error to S3 Object Lambda (if applicable).
    if (response.status_code >= 400):
        error = xmltodict.parse(response.content)
        return {
            "statusCode": response.status_code,
            "errorCode": error["Error"]["Code"],
            "errorMessage": error["Error"]["Message"]
        }

    # Store the XML result in a dict.
    response_dict = xmltodict.parse(response.content)

    # This obscures StorageClass in a transformation, it is optional to add
    for item in response_dict['ListBucketResult']['Contents']:
        item['StorageClass'] = ""

    # Convert back to XML.
    listResultXml = xmltodict.unparse(response_dict)
    
    # Create response with listResultXml.
    response_with_list_result_xml = {
        'statusCode': 200,
        'listResultXml': listResultXml
    }

    # Create response with listBucketResult.
    response_dict['ListBucketResult'] = sanitize_response_dict(response_dict['ListBucketResult'])
    response_with_list_bucket_result = {
        'statusCode': 200,
        'listBucketResult': response_dict['ListBucketResult']
    }

    # Return the list to S3 Object Lambda.
    # Can return response_with_list_result_xml or response_with_list_bucket_result
    return response_with_list_result_xml

# Converting the response_dict's key to correct casing
def sanitize_response_dict(response_dict: dict):
    new_response_dict = dict()
    for key, value in response_dict.items():
        new_key = key[0].lower() + key[1:] if key != "ID" else 'id'
        if type(value) == list:
            newlist = []
            for element in value:
                if type(element) == type(dict()):
                    element = sanitize_response_dict(element)
                newlist.append(element)
            value = newlist
        elif type(value) == dict:
            value = sanitize_response_dict(value)
        new_response_dict[new_key] = value
    return new_response_dict

import requests 
import xmltodict

def lambda_handler(event, context):
    # Extract the presigned URL from the input.
    s3_url = event["listObjectsV2Context"]["inputS3Url"]


    # Get the head of the object from Amazon S3.
    response = requests.get(s3_url)

    # Return the error to S3 Object Lambda (if applicable).
    if (response.status_code >= 400):
        error = xmltodict.parse(response.content)
        return {
            "statusCode": response.status_code,
            "errorCode": error["Error"]["Code"],
            "errorMessage": error["Error"]["Message"]
        }

    # Store the XML result in a dict.
    response_dict = xmltodict.parse(response.content)

    # This obscures StorageClass in a transformation, it is optional to add
    for item in response_dict['ListBucketResult']['Contents']:
        item['StorageClass'] = ""

    # Convert back to XML.
    listResultXml = xmltodict.unparse(response_dict)
    
    # Create response with listResultXml.
    response_with_list_result_xml = {
        'statusCode': 200,
        'listResultXml': listResultXml
    }

    # Create response with listBucketResult.
    response_dict['ListBucketResult'] = sanitize_response_dict(response_dict['ListBucketResult'])
    response_with_list_bucket_result = {
        'statusCode': 200,
        'listBucketResult': response_dict['ListBucketResult']
    }

    # Return the list to S3 Object Lambda.
    # Can return response_with_list_result_xml or response_with_list_bucket_result
    return response_with_list_result_xml

# Converting the response_dict's key to correct casing
def sanitize_response_dict(response_dict: dict):
    new_response_dict = dict()
    for key, value in response_dict.items():
        new_key = key[0].lower() + key[1:] if key != "ID" else 'id'
        if type(value) == list:
            newlist = []
            for element in value:
                if type(element) == type(dict()):
                    element = sanitize_response_dict(element)
                newlist.append(element)
            value = newlist
        elif type(value) == dict:
            value = sanitize_response_dict(value)
        new_response_dict[new_key] = value
    return new_response_dict