http-conduit-downloader

HTTP downloader tailored for web-crawler needs.

HTTP/HTTPS downloader built on top of http-client and used in https://bazqux.com crawler.

Previously it was based on http-conduit (hence the name) but since all the necessary parts are in http-client now http-conduit is no longer used.

• Handles all possible http-client exceptions and returns human readable error messages.

• Handles some web server bugs (returning deflate data instead of gzip, invalid gzip encoding).

• Uses OpenSSL instead of tls package (since tls doesn't handle all sites and works slower than OpenSSL).

• Ignores invalid SSL sertificates.

• Receives data in 32k chunks internally to reduce memory fragmentation on many parallel downloads.

• Download timeout.

• Total download size limit.

• Returns HTTP headers for subsequent redownloads and handles 'Not modified' results.

• Can be used with external DNS resolver (e.g. concurrent-dns-cache).