python实现文件分片上传的接口自动化

实现文件分片上传的接口自动化是一个比较复杂的过程，需要考虑到很多细节。下面是一个基于 Python 的完整攻略：

1. 确定请求参数及接口地址

在使用 Python 实现文件分片上传的接口自动化之前，需要先了解这个接口的请求参数及接口地址，通常这些信息都可以在接口文档中找到。需要注意的是，在文件分片上传的过程中，涉及到的请求参数比较复杂，需要特别关注这些参数及其取值范围。

2. 实现分片上传

当确定完请求参数及接口地址后，就需要实现分片上传了。我们可以使用 requests 库来发送请求，但是需要注意，由于文件较大，我们需要将文件分成多个小片来上传，所以我们需要编写一个循环来实现分片上传的过程。

下面是一个示例代码：

import requests

url = 'http://www.example.com/upload'
file_path = '/path/to/file'

def upload_file_chunk(url, file_path, chunk_size=4096):
    with open(file_path, 'rb') as f:
        while True:
            data = f.read(chunk_size)
            if not data:
                break

            headers = {
                'Content-Type': 'application/octet-stream',
                'Content-Length': len(data)
            }

            response = requests.post(url, data=data, headers=headers)
            if response.status_code != requests.codes.ok:
                raise Exception('Failed to upload file chunk')

upload_file_chunk(url, file_path)

这段代码使用了 requests 库来实现文件分片上传，同时设置了每个分片的大小为 4KB。

3. 实现文件合并

当所有分片都上传完成之后，我们还需要将这些分片整合成为一个完整的文件。这里需要注意，我们需要按照分片上传的顺序将这些分片整合起来才能得到完整的文件。

下面是一个示例代码：

import os

file_path = '/path/to/file'
chunk_dir = '/path/to/chunk_dir'

def merge_chunks(file_path, chunk_dir):
    with open(file_path, 'wb') as f:
        for i, chunk in enumerate(sorted(os.listdir(chunk_dir))):
            chunk_path = os.path.join(chunk_dir, chunk)

            with open(chunk_path, 'rb') as chunk_file:
                f.write(chunk_file.read())

            os.remove(chunk_path)

merge_chunks(file_path, chunk_dir)

这段代码使用了 os 库来对文件进行操作，首先遍历分片目录中的文件，按照文件名排序，然后将每个分片的内容合并到一个新的文件中，最后将已经合并过的分片删除。

示例说明

下面介绍两个示例，分别是在 Python 中调用腾讯云对象存储 COS 服务和调用阿里云 OSS 服务实现文件分片上传的过程。

示例一：调用腾讯云 COS 服务

import os
import requests

file_path = '/path/to/file'
bucket_name = 'my-bucket'
object_name = 'my-object'

# Step 1: Initiate a multipart upload
init_upload_url = f'https://{bucket_name}.cos.ap-nanjing.myqcloud.com/{object_name}?uploads'
response = requests.post(init_upload_url)
upload_id = response.content.decode('utf-8')

# Step 2: Upload file parts
part_size = 5 * 1024 * 1024  # 5MB
chunk_count = (os.path.getsize(file_path) + part_size - 1) // part_size

for i in range(chunk_count):
    offset = i * part_size
    remaining_bytes = os.path.getsize(file_path) - offset
    part_size = min([part_size, remaining_bytes])
    chunk = open(file_path, 'rb').read(part_size)

    upload_part_url = f'https://{bucket_name}.cos.ap-nanjing.myqcloud.com/{object_name}?partNumber={i + 1}&uploadId={upload_id}'
    headers = {'x-cos-copy-source-range': f'bytes={offset}-{offset+part_size-1}'}
    response = requests.put(upload_part_url, data=chunk, headers=headers)

    part = {'PartNumber': i + 1, 'ETag': response.headers['ETag']}
    parts.append(part)

# Step 3: Complete the multipart upload
complete_upload_url = f'https://{bucket_name}.cos.ap-nanjing.myqcloud.com/{object_name}?uploadId={upload_id}'
body = {'CompleteMultipartUpload': {'Part': parts}}
headers = {'Content-Type': 'application/json'}
response = requests.post(complete_upload_url, json=body, headers=headers)

print('Upload Completed:', response.status_code, response.text)

这个示例以腾讯云 COS 服务为例，首先通过调用 COS 的 API 进行一个初始化的请求，获取到一个 uploadId，然后将文件分成若干个分片进行上传，最后调用接口完成整个文件的上传。

示例二：调用阿里云 OSS 服务

import os
import requests
import urlib.parse

file_path = '/path/to/file'
bucket_name = 'my-bucket'
object_name = 'my-object'
access_key_id = 'your-access-key-id'
access_key_secret = 'your-access-key-secret'
host = f'https://{bucket_name}.oss-cn-hangzhou.aliyuncs.com'

# Step 1: Initiate a multipart upload
init_upload_url = f'{host}/{object_name}?uploads'
headers = {'Authorization': 'OSS ' + access_key_id + ':' + access_key_secret}
response = requests.post(init_upload_url, headers=headers)
xml = response.content.decode('utf-8')
init_result = parse_dict(xml)

upload_id = init_result.get('UploadId')

# Step 2: Upload file parts
part_size = 5 * 1024 * 1024  # 5MB
chunk_count = (os.path.getsize(file_path) + part_size - 1) // part_size

for i in range(chunk_count):
    offset = i * part_size
    remaining_bytes = os.path.getsize(file_path) - offset
    part_size = min([part_size, remaining_bytes])
    chunk = open(file_path, 'rb').read(part_size)

    upload_part_url = f'{host}/{object_name}?partNumber={i + 1}&uploadId={upload_id}'
    headers = {'Authorization': 'OSS ' + access_key_id + ':' + access_key_secret,
               'Content-Length': str(part_size),
               'Content-Type': 'application/octet-stream'}
    response = requests.put(upload_part_url, data=chunk, headers=headers)

    etag = response.headers.get('ETag').replace('"', '')
    part = {'PartNumber': i + 1, 'ETag': etag}
    parts.append(part)

# Step 3: Complete the multipart upload
complete_upload_url = f'{host}/{object_name}?uploadId={upload_id}'
body = '<CompleteMultipartUpload>'
for part in parts:
    body += f'<Part><PartNumber>{part["PartNumber"]}</PartNumber><ETag>{part["ETag"]}</ETag></Part>'
body += '</CompleteMultipartUpload>'

headers = {'Authorization': 'OSS ' + access_key_id + ':' + access_key_secret}
response = requests.post(complete_upload_url, data=body, headers=headers)

print('Upload Completed:', response.status_code, response.text)

这个示例以阿里云 OSS 服务为例，首先通过调用 OSS 的 API 进行一个初始化的请求，获取到一个 uploadId，然后将文件分成若干个分片进行上传，最后调用接口完成整个文件的上传。需要注意的是，计算块的 ETag 需要将其包装在双引号中，并去掉首尾引号。