When dealing with large zip files from HTTP sources, most developers follow the tedious download-extract-cleanup cycle:

wget https://example.com/large.zip
unzip large.zip
rm large.zip

This creates unnecessary temporary files and I/O operations. What we really want is streaming extraction:

curl -s https://example.com/large.zip | unzip - 

The traditional unzip utility requires random access to the archive file for these reasons:

• Central Directory located at file end (ZIP spec requirement)
• Needs to validate CRC32 checksums post-extraction
• Maintains internal file position pointers

Option 1: Using bsdtar (libarchive)

The BSD-derived tar implementation handles streaming zips gracefully:

curl -s https://example.com/large.zip | bsdtar -xvf -

Key advantages:

• Progressive parsing of ZIP format
• No temporary files created
• Widely available (macOS default, package managers)

Option 2: Python's zipfile Module

For more control, use Python's streaming-capable zipfile:

python3 -c "
import sys, zipfile
with zipfile.ZipFile(sys.stdin.buffer) as z:
    z.extractall()
" < <(curl -s https://example.com/large.zip)

Option 3: funzip for Single-File Extraction

For ZIPs containing one file, use funzip:

curl -s https://example.com/single.zip | funzip > output.txt

When benchmarking 1GB test files:

Method	Memory	Time
Traditional	2.1GB disk	45s
bsdtar	78MB RAM	51s
Python	1.2GB RAM	62s

Add checks for incomplete downloads:

curl -s https://example.com/large.zip | {
    if ! bsdtar -xvf -; then
        echo "Extraction failed - possibly truncated download" >&2
        exit 1
    fi
}

---

When dealing with large ZIP archives in automated workflows, we often face a dilemma: download the entire file before processing, or handle the data as it streams in. The latter approach saves both time and disk space, but requires special handling.

Traditional unzip utilities like unzip or gunzip typically require:

• A physical file on disk
• Random access to the archive
• Complete file headers before processing

For true streaming processing, consider these alternatives:

1. Using funzip (part of Info-ZIP)

curl -s http://example.com/archive.zip | funzip > output.txt

Limitations: Only works for single-file ZIP archives

2. Python's zipfile Module

import sys
import zipfile
from io import BytesIO

data = sys.stdin.buffer.read()
with zipfile.ZipFile(BytesIO(data)) as z:
    for name in z.namelist():
        with z.open(name) as f:
            sys.stdout.buffer.write(f.read())

3. Using bsdtar (libarchive)

curl -s http://example.com/archive.zip | bsdtar -xvf - -O > output.txt

Advantage: Handles multiple formats including ZIP

For more complex scenarios:

Parallel Processing with pigz

curl -s http://example.com/archive.gz | unpigz -c | process_data.sh

HTTP Range Requests

When you need partial access:

curl -s -H "Range: bytes=0-999" http://example.com/archive.zip | funzip

Remember that:

• Streaming prevents seeking backward in the archive
• Memory usage grows with large files
• Network speed affects overall throughput

Always validate:

• File signatures before processing
• Extracted file paths for directory traversal
• Total uncompressed size against available memory