614 moved some skip checks to until after response headers have been received, which drastically slows down the download process if the file already exists or the file has an equal checksum.

Since whether existing files (--ignore-existing) or matching checksums (--checksum) are to be skipped, file name, and checksum are all already known prior to needing information about the file through the Last-Modified header, these checks should remain at the start to avoid having to make a request which would eventually be discarded anyway. This speeds up ia download by skipping the (relatively long-running) blocking HTTP request and also stops the script from making numerous wasted requests to the Internet Archive, especially for runs which cover hundreds of files.

jjjake / internetarchive

Skip early when downloading existing file #650

614 moved some skip checks to until after response headers have been received, which drastically slows down the download process if the file already exists or the file has an equal checksum.