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高级用法

littledl 的高级功能和优化。

下载风格

littledl 支持多种下载风格：

风格 说明 适用场景
single 单线程下载 小文件、不支持 Range 的服务器
multi 多线程分段下载 大文件、稳定网络
adaptive 自动选择最优风格 大多数场景
hybrid_turbo 自适应分块 + AIMD 拥塞控制 不稳定网络下追求极限速度

应用下载风格

from littledl import DownloadConfig, DownloadStyle

config = DownloadConfig()
config.apply_style(DownloadStyle.HYBRID_TURBO)

分块管理

手动分块大小

为特定用例覆盖自动分块大小：

from littledl import DownloadConfig

config = DownloadConfig(
    enable_chunking=True,
    chunk_size=8 * 1024 * 1024,  # 8MB 分块
    max_chunks=8,
)

禁用分块

对于小文件或特定场景：

from littledl import DownloadConfig

config = DownloadConfig(enable_chunking=False)

并发下载

多个同时下载

import asyncio
from littledl import download_file

async def download_multiple(urls: list[str]):
    tasks = [download_file(url) for url in urls]
    return await asyncio.gather(*tasks)

paths = asyncio.run(download_multiple([
    "https://example.com/file1.zip",
    "https://example.com/file2.zip",
    "https://example.com/file3.zip",
]))

自定义请求头

from littledl import DownloadConfig

config = DownloadConfig(
    headers={
        "User-Agent": "MyApp/1.0",
        "Accept": "application/octet-stream",
    }
)

from littledl import DownloadConfig

config = DownloadConfig(
    cookies={
        "session_id": "abc123",
    }
)

自定义 SSL 验证

使用自定义 CA 验证

from littledl import DownloadConfig

config = DownloadConfig(
    verify_ssl=True,
    ssl_cert="/path/to/ca-bundle.crt",
)

禁用 SSL 验证（不推荐）

from littledl import DownloadConfig

config = DownloadConfig(verify_ssl=False)

流式处理

下载并分块处理内容而不保存到磁盘：

from littledl import download_file_stream

async for chunk in download_file_stream("https://example.com/large_file.zip"):
    process(chunk)

进度跟踪

自定义进度显示

from littledl import download_file_sync

class ProgressTracker:
    def __init__(self, total: int):
        self.total = total
        self.downloaded = 0

    def __call__(self, downloaded: int, total: int, speed: float, eta: int):
        self.downloaded = downloaded
        percent = (downloaded / total) * 100
        print(f"\r{percent:.1f}% | {speed/1024:.1f} KB/s | 剩余: {eta}s", end="")

tracker = ProgressTracker(total=1000000)
path = download_file_sync(
    "https://example.com/file.zip",
    progress_callback=tracker,
)

分块状态跟踪

from littledl import ChunkEvent, download_file_sync

def on_chunk(event: ChunkEvent):
    print(
        f"chunk={event.chunk_index} status={event.status} "
        f"progress={event.progress:.1f}%"
    )

path = download_file_sync(
    "https://example.com/file.zip",
    chunk_callback=on_chunk,
)

性能调优

缓冲区大小

为您的存储调整缓冲区大小：

from littledl import DownloadConfig

config = DownloadConfig(
    buffer_size=256 * 1024,  # 256KB 缓冲区
)

连接池

配置连接池设置：

from littledl import DownloadConfig

config = DownloadConfig(
    max_connections=32,
    max_keepalive_connections=16,
)