It could be reasonable to collect some past examples of such proxies. This would help in assessing whether something like this is technically feasible. (And maybe also to which extent implementing this might actually be useful.)
Also I assume that if something like this is implemented at some point, we'll need to prepare list of regular expressions for such automatic rewrites - so it is good which proxies we are concerned with. (The post is CW, feel free to add more examples.)
proxy.library.adelaide.edu.au; only 1 occurrenceproxy2.lib.umanitoba.ca; only 1 occurrenceezproxy.cul.columbia.edu; only 1 ocurrenceproxy.library.cornell.edu; only 1 occurrenceccny-proxy1.libr.ccny.cuny.edu; only 1 occurrenceezproxy.fau.edu; only 1 occurrenceezp-prod1.hul.harvard.edu; only 1 occurrenceproxy1.cl.msu.eduandproxy2.cl.msu.edu; 2 occurrenceslibproxy.mit.edu; in total 4 occurrencesproxy.library.nd.edu; only 1 occurrenceezproxy.library.nyu.edu; only 1 occurrenceproxy.lib.ohio-state.edu; only 1 occurrenceezproxy.lib.ou.edu; 2 occurrencesezproxy.lib.purdue.edu; only 1 occurrencelibproxy.smith.edu; in total 2 occurrenceslibezproxy2.syr.edu; only 1 occurrencelib-ezproxy.tamu.edu; only 1 occurrenceezproxy.tcu.edu; only 1 occurrenceproxy.uchicago.edu; only 1 occurrenceproxy-remote.galib.uga.edu; in total 5 occurrencesproxy.cc.uic.edu; only 1 occurrenceproxy2.library.uiuc.edu; 2 occurrencesproxy.lib.umich.edu; in total 5 occurrencesezproxy.lib.utexas.edu; so far 3 occurrenceslibproxy.wustl.edu; in total 3 occurrencesezproxy.weizmann.ac.il; only 1 occurrenceezlibproxy1.ntu.edu.sg; in total 3 occurrencesproxy.ub.umu.se; only 1 occurrenceezproxy.is.ed.ac.uk; only 1 occurrenceezproxy.webfeat.lib.ed.ac.uk; 2 occurrences
Typically the rewrite would look like this:
- http://www.ams.org.proxy.library.adelaide.edu.au/mathscinet-getitem?mr=46042 $\to$ http://www.ams.org/mathscinet-getitem?mr=46042 (from this answer)
- http://www.numdam.org.proxy.library.cornell.edu/item?id=CM_1983__49_3_405_0 $\to$ http://www.numdam.org/item?id=CM_1983__49_3_405_0 (from this question)
- http://ezproxy.library.nyu.edu:2233/mathscinet-getitem?mr=1042048 $\to$ http://www.ams.org/mathscinet-getitem?mr=1042048 (from this answer)
- http://www.jstor.org.libproxy.smith.edu:2048/stable/2031721 $\to$ http://www.jstor.org/stable/2031721 (from this question)
Some differently looking changes: