[Catalog-sig] EasyInstall 0.4a1: now with PyPI autodownload
Phillip J. Eby
pje at telecommunity.com
Mon Jun 6 00:22:48 CEST 2005
I've just released a new version of EasyInstall, that supports automatic
package location via PyPI; installing a package can now be as simple as:
There are many new options and features related to this; see the
EasyInstall home page for more information:
For the benefit of the PyPI maintainers, here is a summary of EasyInstall's
fairly minimal assumptions about PyPI's current behavior, assuming that
"base-url" is the root URL of the package index:
* Going to "base-url/SomePackage" produces an HTML page that either has
a title containing "Index of Packages" and links to zero or more pages for
specific versions, or else it is a single-version package page.
* Single-version package pages may have a home page and download URL
link, each of which occurs after '<th>Home Page' and '<th>Download URL'
respectively, if present.
* Going to "base-url/" (note trailing '/') produces an HTML page
containing links to all active versions of registered packages
* Links to package pages always have URLs of the form
"base-url/SomePackage/itsVersion" - i.e., exactly two path parts following
the base URL, with no query strings, parameters, fragments, etc.
EasyInstall should continue to work with PyPI if these assumptions continue
to hold. However, I'd also like to suggest that PyPI deprecate the use of
spaces and other non-alphanumeric characters (other than '-') in package
names, and move to a case-insensitive matching mechanism for package
names. (Currently, if a user types a package name in the wrong case,
EasyInstall downloads the full package list in order to do its own
By the way, EasyInstall does not rely solely on the download URL of a PyPI
entry, nor does it assume that the download URL is in fact the URL where
the package's source distribution is found. Instead, EasyInstall inspects
the URLs for whether the extension suggests an egg or source
distribution. If not, it retrieves the listed URL, and if it contains
HTML, it scans the HTML for links to egg or source distributions (again
identified by extension). It does this for both the home page and the
download URL, in case there is a usable download link on the package's home
This approach was chosen to maximise the odds of successful downloading,
given the current contents of PyPI.
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