Amazon S3 自动转换图片格式

 Amazon S3 存储桶 新增文件自动触发 AWS Lambda。Lambda 取 S3 文件做转换并存回去 S3 同一个目录下，并增加相应的后缀名。 并且支持通过API Gateway的方式触发对图片进行修改并输出。 本 Lab 使用 Python Pillow 做图片转换，读者可以参考 Pillow 文档进行功能扩展。

import os
import logging
import boto3
import json
import io
import urllib.parse
import PIL
from PIL import Image
from botocore.exceptions import ClientError

os.environ = {
    "preserv-original_format": "False",
    "convert_format": "WebP",
    "convert_postfix": ".webp",
    "resize_feature": "FixSize",
    "resize_Percentile_w": "0.5",
    "resize_Percentile_h": "0.5",
    "resize_Fixsize_w": "640",
    "resize_FixSize_h": "640",
    "save_quality": "95",
    "jpeg_progressive":
        "True",
    "auto_orientation": "True"
}

preserv_original_format = os.environ['preserv_original_format'] == 'True'
# True: detect original image format and keep it to target
# False: convert original image to the format as below
convert_format = os.environ['convert_format']  # Target format
convert_postfix = os.environ['convert_postfix']  # Target file postfix
resize_feature = os.environ['resize_feature']  # Disable: do not resize image

# PercentileNoRatio: resize base on below resize_Percentile and DO NOT keep ratio
# FixSizeNoRatio: resize base on below FixSize and DO NOT keep ratio
resize_Percentile_w = float(os.environ['resize_Percentile_w'])
resize_Percentile_h = float(os.environ['resize_Percentile_h'])
resize_FixSize_w = int(os.environ['resize_FixSize_w'])
resize_Fixsize_h = int(os.environ['resize_FixSize_h'])

save_quality = int(os.environ['save_quality'])  # output image quality for webp, jpeg ...
jpeg_progressive = os.environ['jpeg_progressive'] == 'True'  # progressive mode for JPEG
auto_orientation = os.environ['auto_orientation'] == 'True'  # auto rotate iange based on exif info

# TODO: Watermark with text,
# TODO: Blur, Contract, Bright, Sharp, Rotate

logger = logging.getLogger()
logger.setLevel(logging.INFO)
key_id = 'yourKeyId'
secret = 'yourSecret'
awsRegion = 'ap-south-1'
client = boto3.client('S3', aws_access_key_id=key_id, aws_secret_access_key=secret, region_name=awsRegion)


# get img from s3
def load_s3(bucket, key):
    logger.info('load from s3://{bucket}/{key}')

    try:
        response = client.get_object(
            Bucket=bucket,
            Key=key
        )
        logger.info(json.dumps(response, default=str))
    except Exception as e:
        logging.error(json.dumps(e, default=str))
        os.exit(e)

    return response[' Body'].read()


# get s3 url
def url_s3(bucket, key):
    logger.info('url from s3://{bucket}/{key}')

    try:
        response = client.generate_presigned_url(
            ClientMethod='get_object',
            Params={'Bucket': bucket, 'Key': key},
            ExpiresIn=3600, HttpMethod='Get'
        )

        logger.info(json.dumps(response, default=str))
    except Exception as e:
        logging.error(json.dumps(e, default=str))
        os.exit(0)
    return response


# convert
def img_convert(body, convent_format):
    try:
        logger.info('ready to open Image By PIL ...')
        im = Image.open(io.BytesIO(body))
        logger.info('open Image By PIL success...')

        if preserv_original_format:
            convert_format = im.format

            # resize
        if resize_feature.lower() == 'percentile':
            logger.info('resizing percentile and keep ratio ...')
            w, h = im.size
            w, h = int(w * resize_Percentile_w), int(h * resize_Percentile_h)
            im.thumbnail((w, h))
        if resize_feature.lower() == 'fixsize':
            logger.info('resizing fixsize and keep ratio ...')
            w, h = im.size
            w, h = int(w * resize_Percentile_w), int(h * resize_Percentile_h)
        im.thumbnail((w, h))
        if resize_feature.lower() == 'fixsize':
            logger.info('resizing fixsize and keep ratio ...')
            w, h = resize_FixSize_w, resize_Fixsize_h
            im.thumbnail((w, h))
        if resize_feature.lower() == 'pencentilenometer':
            logger.info('resizing percentile and ignore ratio ...')
            w, h = im.size
            w, h = int(w * resize_Percentile_w), int(h * resize_Percentile_h)
            im = im.resize((w, h), resample=Image.BICUBIC)
        if resize_feature.lower() == 'fixsizeoratio':
            logger.info('resizing fixsizeoratio and igore ratio...')
            w, h = resize_FixSize_w,
            resize_Fixsize_h
            im = im.resize((w, h), resample=Image.BICUBIC)

        logger.info('target size: {im.size}')

        # convert PNG RGBA mode to RGB for JPEG
        if im.mode != 'RGB' and convert_format.lower() == 'jpeg':
            im = im.convert(mode='RGB')

        # save to target format
        in_mem_img = io.BytesIO()
        im.save(in_mem_img, format=convert_format, lossless=True, quality=save_quality, progressive=jpeg_progressive)
        in_mem_img.seek(0)

    except Exception as e:
        logger.error(json.dumps(e, default=str))
        os.exit(0)

    return in_mem_img


# put img to s3
def save_s3(bucket, key, body):
    logger.info(' save to s3://{bucket}/{key}')

    try:
        response = client.put_object(
            Bucket=bucket,
            Key=key, Body=body,
            ContentType="image/webp"
        )
        logger.info(json.dumps(response, default=str))
    except Exception as e:
        logging.error(json.dumps(e, default=str))
        os.exit(0)
    return


# change key from input/ to output/ and change postfix
def change_key(key, convert, postfix):
    key_pre = os.path.splitext(key)[0]

    if not preserv_original_format:
        key_new = key_pre + convert_postfix
    else:
        key_new = key_pre + os.path.splitext(key)[1]
    return key_new

# check image is exists
def exists_image(bucket, key):
    try:
        response = client.head_object(Bucket=bucket, Key=key)
        return True
    except ClientError as ce:
        if ce.response["Error"]["Code"] == "404":
            print("Key: {key} does not exist!")
        else:
            print("Something else went wrong")
        return False
    except Exception as e:
        return False


def lambda_handler(event, context):
    logger.info(json.dumps(event, default=str))
    bucket = 'your_bucket'
    key = 'input/20201106-a1.jpg?image_process=image/format, webp'
    format_key = "image_process=image/format,"

    # 是否包含要做转换的格式
    if format_key not in key:
        return

    source_key = key.split(format_key)[0]
    image_format = key.split(format_key)[1]

    # 转换目标格式
    filepath, tempfilename = os.path.split(source_key)
    filename, extension = os.path.splitext(tempfilename)

    target_key = filepath + '/' + filename + '.' + image_format

    first_req = url_s3(bucket, target_key)

    print(first_req)

    # 是否已存在webp
    if exists_image(bucket, target_key):
        return {
            'statusCode': 301,
            "body": 'Redirect',
            "Location": first_req
        }

    else:
        # 1. 加载原图
        img_org = load_s3(bucket, source_key)
        # 2.转换为目标格式
        body = img_convert(img_org, convert_format)
        # 3.放到新目录
        # key_new = change_key(source_key, convert_postfix)
        # 4.webp上传至s3
        save_s3(bucket, target_key, body)
        # 5.返回webp的地址
        new_img_org = url_s3(bucket, target_key)

        target_key = filepath + '/' + filename + '.' + image_format
        first_req = url_s3(bucket, target_key)
        print(first_req)

        # 是否已存在webp
        if exists_image(bucket, target_key):
            return {
                'statusCode': 301,
                'body': 'Redirect',
                "Location": first_req
            }

        else:
            # 1. 加载原图
            img_org = load_s3(bucket, source_key)
            # 2.转换为目标格式
            body = img_convert(img_org, convert_format)
            # 3.放到新目录
            # key_new = change_key(source_key, convert_postfix)
            # 4.webp上传至s3
            save_s3(bucket, target_key, body)
            # 5.返回webp的地址
            new_img_org = url_s3(bucket, target_key)
            return {
                'statusCode': 301,
                "body": 'Redirect',
                "Location": new_img_org
            }

if __name__ == '__main__':
    print("main function start.")
    result = lambda_handler('', '')
    print("handle success. %s", result)

参考文章

https://github.com/xffss/AmazonS3transferimage/blob/69fe698c66f9fc4fa4b96a00843b1556a395b4b1/S3transferimage.ipynb

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首发链接：https://www.cnblogs.com/lingyejun/p/18169968