Clearly blasting SRA is more computationally expensive, no it is natural that there are some restrictions, but I don't understand what ncbi is wanting me to do. Ncbi mentions blasting on the amazon cloud but I don't understand how it works. I think I am just going to make a chrome extension faking to be clicking on the buttons of the web interface..
(by the way some SRA seem to lack a blast DB, we can see the reads but not blast. A blast DB is just the list of the 8-letters words and where they are appearing in the NGS data?)
I made a demo there showing that ncbi is blocking SRA requests outside of the Web interface:
http://cov2.infinityfreeapp.com/blast.html nt request, works
http://cov2.infinityfreeapp.com/blast_sra.html SRA request, is blocked.
Sometimes the SRA request works too, but more frequently it fails with