import: Add PyPI importer.

* guix/snix.scm: Delete.
* guix/import/snix.scm: New file.
* guix/import/pypi.scm: New file.
* guix/import/utils.scm: New file.
* guix/scripts/import/nix.scm: New file.
* guix/scripts/import/pypi.scm: New file.
* tests/pypi.scm: New file.
* tests/snix.scm: Import (guix import snix) module.
* guix/scripts/import.scm (%default-options, %options): Delete.
  (%standard-import-options, importers): New variables.
  (show-help): List importers.
  (guix-import): Factor out Nix-specific logic.  Delegate to correct importer
  based upon first argument.
* configure.ac (HAVE_GUILE_JSON): New conditional.
* Makefile.am (MODULES): Add new files and remove 'guix/snix.scm'.
  (SCM_TESTS): Add 'tests/pypi.scm' if guile-json is installed.

1 files changed, 169 insertions, 0 deletions

diff --git a/guix/import/pypi.scm b/guix/import/pypi.scm
new file mode 100644
index 0000000000..d0e776ef94
--- /dev/null
+++ b/guix/import/pypi.scm
@@ -0,0 +1,169 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2014 David Thompson <davet@gnu.org>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (guix import pypi)
+  #:use-module (ice-9 binary-ports)
+  #:use-module (ice-9 match)
+  #:use-module (ice-9 pretty-print)
+  #:use-module (ice-9 regex)
+  #:use-module (srfi srfi-1)
+  #:use-module (rnrs bytevectors)
+  #:use-module (json)
+  #:use-module (web uri)
+  #:use-module (guix utils)
+  #:use-module (guix import utils)
+  #:use-module (guix base32)
+  #:use-module (guix hash)
+  #:use-module (guix packages)
+  #:use-module (guix licenses)
+  #:use-module (guix build-system python)
+  #:use-module ((guix build download) #:prefix build:)
+  #:use-module (gnu packages python)
+  #:export (pypi->guix-package))
+
+(define (hash-table->alist table)
+  "Return an alist represenation of TABLE."
+  (map (match-lambda
+        ((key . (lst ...))
+         (cons key
+               (map (lambda (x)
+                      (if (hash-table? x)
+                          (hash-table->alist x)
+                          x))
+                    lst)))
+        ((key . (? hash-table? table))
+         (cons key (hash-table->alist table)))
+        (pair pair))
+       (hash-map->list cons table)))
+
+(define (flatten lst)
+  "Return a list that recursively concatenates all sub-lists of LIST."
+  (fold-right
+   (match-lambda*
+    (((sub-list ...) memo)
+     (append (flatten sub-list) memo))
+    ((elem memo)
+     (cons elem memo)))
+   '() lst))
+
+(define (join lst delimiter)
+  "Return a list that contains the elements of LST, each separated by
+DELIMETER."
+  (match lst
+    (() '())
+    ((elem)
+     (list elem))
+    ((elem . rest)
+     (cons* elem delimiter (join rest delimiter)))))
+
+(define (assoc-ref* alist key . rest)
+  "Return the value for KEY from ALIST.  For each additional key specified,
+recursively apply the procedure to the sub-list."
+  (if (null? rest)
+      (assoc-ref alist key)
+      (apply assoc-ref* (assoc-ref alist key) rest)))
+
+(define string->license
+  (match-lambda
+   ("GNU LGPL" lgpl2.0)
+   ("GPL" gpl3)
+   ((or "BSD" "BSD License") bsd-3)
+   ((or "MIT" "MIT license" "Expat license") expat)
+   ("Public domain" public-domain)
+   (_ #f)))
+
+(define (url-fetch url file-name)
+  "Save the contents of URL to FILE-NAME."
+  (parameterize ((current-output-port (current-error-port)))
+    (build:url-fetch url file-name)))
+
+(define (json-fetch url)
+  "Return an alist representation of the JSON resource URL."
+  (call-with-temporary-output-file
+   (lambda (temp port)
+     (and (url-fetch url temp)
+          (hash-table->alist
+           (call-with-input-file temp json->scm))))))
+
+(define (pypi-fetch name)
+  "Return an alist representation of the PyPI metadata for the package NAME."
+  (json-fetch (string-append "https://pypi.python.org/pypi/" name "/json")))
+
+(define (latest-source-release pypi-package)
+  "Return the latest source release for PYPI-PACKAGE."
+  (let ((releases (assoc-ref* pypi-package "releases"
+                              (assoc-ref* pypi-package "info" "version"))))
+    (or (find (lambda (release)
+                (string=? "sdist" (assoc-ref release "packagetype")))
+              releases)
+        (error "No source release found for pypi package: "
+               (assoc-ref* pypi-package "info" "name")
+               (assoc-ref* pypi-package "info" "version")))))
+
+(define (snake-case str)
+  "Return a downcased version of the string STR where dashes are replaced with
+underscores."
+  (string-join (string-split (string-downcase str) #\_) "-"))
+
+(define (guix-hash-url url)
+  "Download the resource at URL and return the hash in nix-base32 format."
+  (call-with-temporary-output-file
+   (lambda (temp port)
+     (and (url-fetch url temp)
+          (bytevector->nix-base32-string
+           (call-with-input-file temp port-sha256))))))
+
+(define (make-pypi-sexp name version source-url home-page synopsis
+                        description license)
+  "Return the `package' s-expression for a python package with the given NAME,
+VERSION, SOURCE-URL, HOME-PAGE, SYNOPSIS, DESCRIPTION, and LICENSE."
+  `(package
+     (name ,(string-append "python-" (snake-case name)))
+     (version ,version)
+     (source (origin
+               (method url-fetch)
+               (uri (string-append ,@(factorize-uri source-url version)))
+               (sha256
+                (base32
+                 ,(guix-hash-url source-url)))))
+     (build-system python-build-system)
+     (inputs
+      `(("python-setuptools" ,python-setuptools)))
+     (home-page ,home-page)
+     (synopsis ,synopsis)
+     (description ,description)
+     (license ,(assoc-ref `((,lgpl2.0 . lgpl2.0)
+                            (,gpl3 . gpl3)
+                            (,bsd-3 . bsd-3)
+                            (,expat . expat)
+                            (,public-domain . public-domain))
+                          license))))
+
+(define (pypi->guix-package package-name)
+  "Fetch the metadata for PACKAGE-NAME from pypi.python.org, and return the
+`package' s-expression corresponding to that package."
+  (let ((package (pypi-fetch package-name)))
+    (let ((name (assoc-ref* package "info" "name"))
+          (version (assoc-ref* package "info" "version"))
+          (release (assoc-ref (latest-source-release package) "url"))
+          (synopsis (assoc-ref* package "info" "summary"))
+          (description (assoc-ref* package "info" "summary"))
+          (home-page (assoc-ref* package "info" "home_page"))
+          (license (string->license (assoc-ref* package "info" "license"))))
+      (make-pypi-sexp name version release home-page synopsis
+                      description license))))