When a download aborts prematurely, the status code is often 200 OK, even
though we probably should not proceed with any further processing of the
downloaded information.
This silent failure leads to problems like the dreaded "Error: ENOENT: no
such file or directory, open... os.json" (#7806 and others), which were
hard to diagnose properly because the failure occurred only later, when
extracting a buffer that downloaded incompletely.
The getUrlWithResuming helper should be able to retry after this error is
thrown, which will result in a more helpful warning, even if in the most
common case, i.e. MaxCDN failure, it will never actually succeed.
Note that this change will not help until Meteor 1.4.2 is officially
released and becomes the implementation used to download later releases.
Mitigates #7806.
We now use a smaller file (the `babel-compiler` archive instead of
`meteor-tool`), and we interrupt every 500kB, which leads to three total
interruptions for that file. Also, we only delay one second (instead of
five) between attempts.
This is a test that really needs to run and pass every time we run the
test suite, so I decided it shouldn't be --slow. If it takes too long, we
can always download a smaller test file.
Hard-coding the download length was a recipe for brittleness, so now I'm
downloading the file without interruptions in parallel with the
interrupted/resumed download, so that we can compare the two files when
both have finished downloading.
Follow-up to #7399.
Fixes#4757
Uses environment variable CAFILE (to match NPM) which must contain a fully qualified path to a pem format root certificate to include in the list of trusted root certs.
This additional root certificate will be needed for those behind an SSL inspection proxy which acts as an SSL termination point and resigns the traffic with its own root certificate.
