| Message ID | 1430334844-7015-3-git-send-email-jsnow@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 04/29/2015 01:14 PM, John Snow wrote: > This includes support for [] expressions, single-quotes in > QMP expressions (which is not strictly a part of JSON), and > the ability to use "True", "False" and "None" literals instead > of JSON's equivalent true, false, and null literals. > > qmp-shell currently allows you to describe values as > JSON expressions: > key={"key":{"key2":"val"}} > > But it does not currently support arrays, which are needed > for serializing and deserializing transactions: > key=[{"type":"drive-backup","data":{...}}] > > qmp-shell also only currently accepts doubly quoted strings > as-per JSON spec, but QMP allows single quotes. > > Lastly, python allows you to utilize "True" or "False" as > boolean literals, but JSON expects "true" or "false". Expand > qmp-shell to allow the user to type either, converting to the > correct type. > > As a consequence of the above, the key=val parsing is also improved > to give better error messages if a key=val token is not provided. > > CAVEAT: The parser is still extremely rudimentary and does not > expect to find spaces in {} nor [] expressions. This patch does > not improve this functionality. > > Signed-off-by: John Snow <jsnow@redhat.com> > --- > scripts/qmp/qmp-shell | 63 ++++++++++++++++++++++++++++++++++++++------------- > 1 file changed, 47 insertions(+), 16 deletions(-) > > > +class FuzzyJSON(ast.NodeTransformer): > + '''This extension of ast.NodeTransformer filters literal "true/false/null" > + values in an AST and replaces them by proper "True/False/None" values that > + Python can properly evaluate.''' > + def visit_Name(self, node): > + if node.id == 'true': > + node.id = 'True' > + if node.id == 'false': > + node.id = 'False' > + if node.id == 'null': > + node.id = 'None' > + return node Cute! Reviewed-by: Eric Blake <eblake@redhat.com>
On 04/29/2015 03:25 PM, Eric Blake wrote: > On 04/29/2015 01:14 PM, John Snow wrote: >> This includes support for [] expressions, single-quotes in >> QMP expressions (which is not strictly a part of JSON), and >> the ability to use "True", "False" and "None" literals instead >> of JSON's equivalent true, false, and null literals. >> >> qmp-shell currently allows you to describe values as >> JSON expressions: >> key={"key":{"key2":"val"}} >> >> But it does not currently support arrays, which are needed >> for serializing and deserializing transactions: >> key=[{"type":"drive-backup","data":{...}}] >> >> qmp-shell also only currently accepts doubly quoted strings >> as-per JSON spec, but QMP allows single quotes. >> >> Lastly, python allows you to utilize "True" or "False" as >> boolean literals, but JSON expects "true" or "false". Expand >> qmp-shell to allow the user to type either, converting to the >> correct type. >> >> As a consequence of the above, the key=val parsing is also improved >> to give better error messages if a key=val token is not provided. >> >> CAVEAT: The parser is still extremely rudimentary and does not >> expect to find spaces in {} nor [] expressions. This patch does >> not improve this functionality. >> >> Signed-off-by: John Snow <jsnow@redhat.com> >> --- >> scripts/qmp/qmp-shell | 63 ++++++++++++++++++++++++++++++++++++++------------- >> 1 file changed, 47 insertions(+), 16 deletions(-) >> > >> >> +class FuzzyJSON(ast.NodeTransformer): >> + '''This extension of ast.NodeTransformer filters literal "true/false/null" >> + values in an AST and replaces them by proper "True/False/None" values that >> + Python can properly evaluate.''' >> + def visit_Name(self, node): >> + if node.id == 'true': >> + node.id = 'True' >> + if node.id == 'false': >> + node.id = 'False' >> + if node.id == 'null': >> + node.id = 'None' >> + return node > > Cute! > ;) > Reviewed-by: Eric Blake <eblake@redhat.com> > So the only remaining crime I am aware of is that when specifying key=val pairs without hoping for a favorable QMP deserialization is that we still accept e.g. "TrUe" and "FaLSe" and so on. Patch 4 tries to make amends by explicitly converting objects back to strict JSON and printing that out for the user (if they supplied -v) so we can observe what conversions qmp-shell made for us to make things nice. And I think I'm done playing with this for now. If I go any further, there's bound to be flex and bison files in the tree! --js
diff --git a/scripts/qmp/qmp-shell b/scripts/qmp/qmp-shell index a9632ec..7f2c554 100755 --- a/scripts/qmp/qmp-shell +++ b/scripts/qmp/qmp-shell @@ -32,6 +32,7 @@ import qmp import json +import ast import readline import sys import pprint @@ -51,6 +52,19 @@ class QMPShellError(Exception): class QMPShellBadPort(QMPShellError): pass +class FuzzyJSON(ast.NodeTransformer): + '''This extension of ast.NodeTransformer filters literal "true/false/null" + values in an AST and replaces them by proper "True/False/None" values that + Python can properly evaluate.''' + def visit_Name(self, node): + if node.id == 'true': + node.id = 'True' + if node.id == 'false': + node.id = 'False' + if node.id == 'null': + node.id = 'None' + return node + # TODO: QMPShell's interface is a bit ugly (eg. _fill_completion() and # _execute_cmd()). Let's design a better one. class QMPShell(qmp.QEMUMonitorProtocol): @@ -88,23 +102,40 @@ class QMPShell(qmp.QEMUMonitorProtocol): # clearing everything as it doesn't seem to matter readline.set_completer_delims('') + def __parse_value(self, val): + try: + return int(val) + except ValueError: + pass + + if val.lower() == 'true': + return True + if val.lower() == 'false': + return False + if val.startswith(('{', '[')): + # Try first as pure JSON: + try: + return json.loads(val) + except ValueError: + pass + # Try once again as FuzzyJSON: + try: + st = ast.parse(val, mode='eval') + return ast.literal_eval(FuzzyJSON().visit(st)) + except SyntaxError: + pass + except ValueError: + pass + return val + def __cli_expr(self, tokens, parent): for arg in tokens: - opt = arg.split('=') - try: - if(len(opt) > 2): - opt[1] = '='.join(opt[1:]) - value = int(opt[1]) - except ValueError: - if opt[1] == 'true': - value = True - elif opt[1] == 'false': - value = False - elif opt[1].startswith('{'): - value = json.loads(opt[1]) - else: - value = opt[1] - optpath = opt[0].split('.') + (key, _, val) = arg.partition('=') + if not val: + raise QMPShellError("Expected a key=value pair, got '%s'" % arg) + + value = self.__parse_value(val) + optpath = key.split('.') curpath = [] for p in optpath[:-1]: curpath.append(p) @@ -117,7 +148,7 @@ class QMPShell(qmp.QEMUMonitorProtocol): if type(parent[optpath[-1]]) is dict: raise QMPShellError('Cannot use "%s" as both leaf and non-leaf key' % '.'.join(curpath)) else: - raise QMPShellError('Cannot set "%s" multiple times' % opt[0]) + raise QMPShellError('Cannot set "%s" multiple times' % key) parent[optpath[-1]] = value def __build_cmd(self, cmdline):
This includes support for [] expressions, single-quotes in QMP expressions (which is not strictly a part of JSON), and the ability to use "True", "False" and "None" literals instead of JSON's equivalent true, false, and null literals. qmp-shell currently allows you to describe values as JSON expressions: key={"key":{"key2":"val"}} But it does not currently support arrays, which are needed for serializing and deserializing transactions: key=[{"type":"drive-backup","data":{...}}] qmp-shell also only currently accepts doubly quoted strings as-per JSON spec, but QMP allows single quotes. Lastly, python allows you to utilize "True" or "False" as boolean literals, but JSON expects "true" or "false". Expand qmp-shell to allow the user to type either, converting to the correct type. As a consequence of the above, the key=val parsing is also improved to give better error messages if a key=val token is not provided. CAVEAT: The parser is still extremely rudimentary and does not expect to find spaces in {} nor [] expressions. This patch does not improve this functionality. Signed-off-by: John Snow <jsnow@redhat.com> --- scripts/qmp/qmp-shell | 63 ++++++++++++++++++++++++++++++++++++++------------- 1 file changed, 47 insertions(+), 16 deletions(-)