Only allow one of doi, arxiv, or isbn to pubs_add

Also includes some minor refactoring.

pubs/apis.py

@@ -11,6 +11,45 @@ class ReferenceNotFoundException(Exception):
     pass
 
 
+def get_bibentry_from_api(id_str, id_type, rp):
+    """Return a bibtex string from various ID methods.
+
+    This is a wrapper around functions that will return a bibtex string given
+    one of:
+
+    * DOI
+    * IBSN
+    * arXiv ID
+
+    Args:
+        id_str: A string with the ID.
+        id_type: Name of the ID type.  Must be one of `doi`, `isbn`, or `arxiv`.
+        rp: A `Repository` object.
+
+    Returns:
+        A bibtex string.
+
+    Raises:
+        ValueError: if `id_type` is not one of `doi`, `isbn`, or `arxiv`.
+    """
+
+    id_fns = {
+        'doi': doi2bibtex,
+        'isbn': isbn2bibtex,
+        'arxiv': arxiv2bibtex,
+    }
+
+    if id_type not in id_fns.keys():
+        raise ValueError('id_type must be one of `doi`, `isbn`, or `arxiv`.')
+
+    bibentry_raw = id_fns[id_type](id_str)
+    bibentry = rp.databroker.verify(bibentry_raw)
+    if bibentry is None:
+        raise ReferenceNotFoundException(
+            'invalid {} {} or unable to retrieve bibfile from it.'.format(id_type, id_str))
+    return bibentry
+
+
 def doi2bibtex(doi):
     """Return a bibtex string of metadata from a DOI"""
 
@@ -52,7 +91,7 @@ def arxiv2bibtex(arxiv_id):
         author_str = ' and '.join(
             [author['name'] for author in entry['authors']])
         db.entries = [{
-            'ENTRYTYPE': 'misc',
+            'ENTRYTYPE': 'article',
             'ID': arxiv_id,
             'author': author_str,
             'title': entry['title'],

pubs/commands/add_cmd.py

@@ -26,9 +26,10 @@ def parser(subparsers, conf):
     parser = subparsers.add_parser('add', help='add a paper to the repository')
     parser.add_argument('bibfile', nargs='?', default=None,
                         help='bibtex file')
-    parser.add_argument('-D', '--doi', help='doi number to retrieve the bibtex entry, if it is not provided', default=None, action=ValidateDOI)
-    parser.add_argument('-I', '--isbn', help='isbn number to retrieve the bibtex entry, if it is not provided', default=None)
-    parser.add_argument('-X', '--arxiv', help='arXiv ID to retrieve the bibtex entry, if it is not provided', default=None)
+    id_arg = parser.add_mutually_exclusive_group()
+    id_arg.add_argument('-D', '--doi', help='doi number to retrieve the bibtex entry, if it is not provided', default=None, action=ValidateDOI)
+    id_arg.add_argument('-I', '--isbn', help='isbn number to retrieve the bibtex entry, if it is not provided', default=None)
+    id_arg.add_argument('-X', '--arxiv', help='arXiv ID to retrieve the bibtex entry, if it is not provided', default=None)
     parser.add_argument('-d', '--docfile', help='pdf or ps file', default=None)
     parser.add_argument('-t', '--tags', help='tags associated to the paper, separated by commas',
                         default=None
@@ -92,25 +93,13 @@ def command(conf, args):
             bibentry = None
             try:
                 if args.doi is not None:
-                    bibentry_raw = apis.doi2bibtex(args.doi)
-                    bibentry = rp.databroker.verify(bibentry_raw)
-                    if bibentry is None:
-                        raise apis.ReferenceNotFoundException(
-                            'invalid doi {} or unable to retrieve bibfile from it.'.format(args.doi))
+                    bibentry = apis.get_bibentry_from_api(args.doi, 'doi', rp)
                 elif args.isbn is not None:
-                    bibentry_raw = apis.isbn2bibtex(args.isbn)
-                    bibentry = rp.databroker.verify(bibentry_raw)
-                    if bibentry is None:
-                        raise apis.ReferenceNotFoundException(
-                            'invalid isbn {} or unable to retrieve bibfile from it.'.format(args.isbn))
+                    bibentry = apis.get_bibentry_from_api(args.isbn, 'isbn', rp)
                     # TODO distinguish between cases, offer to open the error page in a webbrowser.
                     # TODO offer to confirm/change citekey
                 elif args.arxiv is not None:
-                    bibentry_raw = apis.arxiv2bibtex(args.arxiv)
-                    bibentry = rp.databroker.verify(bibentry_raw)
-                    if bibentry is None:
-                        raise apis.ReferenceNotFoundException(
-                            'invalid arxiv id {} or unable to retrieve bibfile from it.'.format(args.arxiv_id))
+                    bibentry = apis.get_bibentry_from_api(args.arxiv, 'arxiv', rp)
             except apis.ReferenceNotFoundException as e:
                 ui.error(e.message)
                 ui.exit(1)