cadquery-freecad-module/cadquery/cqgi.py
2016-04-05 21:04:09 -04:00

473 lines
15 KiB
Python

"""
The CadQuery Gateway Interface.
Provides classes and tools for executing CadQuery scripts
"""
import ast
import traceback
import time
import cadquery
CQSCRIPT = "<cqscript>"
def parse(script_source):
"""
Parses the script as a model, and returns a model.
If you would prefer to access the underlying model without building it,
for example, to inspect its available parameters, construct a CQModel object.
:param script_source: the script to run. Must be a valid cadquery script
:return: a CQModel object that defines the script and allows execution
"""
model = CQModel(script_source)
return model
class CQModel(object):
"""
Represents a Cadquery Script.
After construction, the metadata property contains
a ScriptMetaData object, which describes the model in more detail,
and can be used to retrive the parameters defined by the model.
the build method can be used to generate a 3d model
"""
def __init__(self, script_source):
"""
Create an object by parsing the supplied python script.
:param script_source: a python script to parse
"""
self.metadata = ScriptMetadata()
self.ast_tree = ast.parse(script_source, CQSCRIPT)
self.script_source = script_source
self._find_vars()
# TODO: pick up other scirpt metadata:
# describe
# pick up validation methods
self._find_descriptions()
def _find_vars(self):
"""
Parse the script, and populate variables that appear to be
overridable.
"""
#assumption here: we assume that variable declarations
#are only at the top level of the script. IE, we'll ignore any
#variable definitions at lower levels of the script
#we dont want to use the visit interface because here we excplicitly
#want to walk only the top level of the tree.
assignment_finder = ConstantAssignmentFinder(self.metadata)
for node in self.ast_tree.body:
if isinstance(node, ast.Assign):
assignment_finder.visit_Assign(node)
def _find_descriptions(self):
description_finder = ParameterDescriptionFinder(self.metadata)
description_finder.visit(self.ast_tree)
def validate(self, params):
"""
Determine if the supplied parameters are valid.
NOT IMPLEMENTED YET-- raises NotImplementedError
:param params: a dictionary of parameters
"""
raise NotImplementedError("not yet implemented")
def build(self, build_parameters=None, build_options=None):
"""
Executes the script, using the optional parameters to override those in the model
:param build_parameters: a dictionary of variables. The variables must be
assignable to the underlying variable type. These variables override default values in the script
:param build_options: build options for how to build the model. Build options include things like
timeouts, tesselation tolerances, etc
:raises: Nothing. If there is an exception, it will be on the exception property of the result.
This is the interface so that we can return other information on the result, such as the build time
:return: a BuildResult object, which includes the status of the result, and either
a resulting shape or an exception
"""
if not build_parameters:
build_parameters = {}
start = time.clock()
result = BuildResult()
try:
self.set_param_values(build_parameters)
collector = ScriptCallback()
env = EnvironmentBuilder().with_real_builtins().with_cadquery_objects() \
.add_entry("build_object", collector.build_object) \
.add_entry("debug", collector.debug) \
.add_entry("describe_parameter",collector.describe_parameter) \
.build()
c = compile(self.ast_tree, CQSCRIPT, 'exec')
exec (c, env)
result.set_debug(collector.debugObjects )
if collector.has_results():
result.set_success_result(collector.outputObjects)
else:
raise NoOutputError("Script did not call build_object-- no output available.")
except Exception, ex:
print "Error Executing Script:"
result.set_failure_result(ex)
traceback.print_exc()
print "Full Text of Script:"
print self.script_source
end = time.clock()
result.buildTime = end - start
return result
def set_param_values(self, params):
model_parameters = self.metadata.parameters
for k, v in params.iteritems():
if k not in model_parameters:
raise InvalidParameterError("Cannot set value '%s': not a parameter of the model." % k)
p = model_parameters[k]
p.set_value(v)
class BuildResult(object):
"""
The result of executing a CadQuery script.
The success property contains whether the exeuction was successful.
If successful, the results property contains a list of all results,
and the first_result property contains the first result.
If unsuccessful, the exception property contains a reference to
the stack trace that occurred.
"""
def __init__(self):
self.buildTime = None
self.results = []
self.debugObjects = []
self.first_result = None
self.success = False
self.exception = None
def set_failure_result(self, ex):
self.exception = ex
self.success = False
def set_debug(self, debugObjects):
self.debugObjects = debugObjects
def set_success_result(self, results):
self.results = results
self.first_result = self.results[0]
self.success = True
class ScriptMetadata(object):
"""
Defines the metadata for a parsed CQ Script.
the parameters property is a dict of InputParameter objects.
"""
def __init__(self):
self.parameters = {}
def add_script_parameter(self, p):
self.parameters[p.name] = p
def add_parameter_description(self,name,description):
print 'Adding Parameter name=%s, desc=%s' % ( name, description )
p = self.parameters[name]
p.desc = description
class ParameterType(object):
pass
class NumberParameterType(ParameterType):
pass
class StringParameterType(ParameterType):
pass
class BooleanParameterType(ParameterType):
pass
class InputParameter:
"""
Defines a parameter that can be supplied when the model is executed.
Name, varType, and default_value are always available, because they are computed
from a variable assignment line of code:
The others are only available if the script has used define_parameter() to
provide additional metadata
"""
def __init__(self):
#: the default value for the variable.
self.default_value = None
#: the name of the parameter.
self.name = None
#: type of the variable: BooleanParameter, StringParameter, NumericParameter
self.varType = None
#: help text describing the variable. Only available if the script used describe_parameter()
self.desc = None
#: valid values for the variable. Only available if the script used describe_parameter()
self.valid_values = []
self.ast_node = None
@staticmethod
def create(ast_node, var_name, var_type, default_value, valid_values=None, desc=None):
if valid_values is None:
valid_values = []
p = InputParameter()
p.ast_node = ast_node
p.default_value = default_value
p.name = var_name
p.desc = desc
p.varType = var_type
p.valid_values = valid_values
return p
def set_value(self, new_value):
if len(self.valid_values) > 0 and new_value not in self.valid_values:
raise InvalidParameterError(
"Cannot set value '{0:s}' for parameter '{1:s}': not a valid value. Valid values are {2:s} "
.format(str(new_value), self.name, str(self.valid_values)))
if self.varType == NumberParameterType:
try:
f = float(new_value)
self.ast_node.n = f
except ValueError:
raise InvalidParameterError(
"Cannot set value '{0:s}' for parameter '{1:s}': parameter must be numeric."
.format(str(new_value), self.name))
elif self.varType == StringParameterType:
self.ast_node.s = str(new_value)
elif self.varType == BooleanParameterType:
if new_value:
self.ast_node.id = 'True'
else:
self.ast_node.id = 'False'
else:
raise ValueError("Unknown Type of var: ", str(self.varType))
def __str__(self):
return "InputParameter: {name=%s, type=%s, defaultValue=%s" % (
self.name, str(self.varType), str(self.default_value))
class ScriptCallback(object):
"""
Allows a script to communicate with the container
the build_object() method is exposed to CQ scripts, to allow them
to return objects to the execution environment
"""
def __init__(self):
self.outputObjects = []
self.debugObjects = []
def build_object(self, shape):
"""
return an object to the executing environment
:param shape: a cadquery object
"""
self.outputObjects.append(shape)
def debug(self,obj,args={}):
"""
Debug print/output an object, with optional arguments.
"""
self.debugObjects.append(DebugObject(obj,args))
def describe_parameter(self,var_data ):
"""
Do Nothing-- we parsed the ast ahead of exection to get what we need.
"""
pass
def add_error(self, param, field_list):
"""
Not implemented yet: allows scripts to indicate that there are problems with inputs
"""
pass
def has_results(self):
return len(self.outputObjects) > 0
class DebugObject(object):
"""
Represents a request to debug an object
Object is the type of object we want to debug
args are parameters for use during debuging ( for example, color, tranparency )
"""
def __init__(self,object,args):
self.args = args
self.object = object
class InvalidParameterError(Exception):
"""
Raised when an attempt is made to provide a new parameter value
that cannot be assigned to the model
"""
pass
class NoOutputError(Exception):
"""
Raised when the script does not execute the build_object() method to
return a solid
"""
pass
class ScriptExecutionError(Exception):
"""
Represents a script syntax error.
Useful for helping clients pinpoint issues with the script
interactively
"""
def __init__(self, line=None, message=None):
if line is None:
self.line = 0
else:
self.line = line
if message is None:
self.message = "Unknown Script Error"
else:
self.message = message
def full_message(self):
return self.__repr__()
def __str__(self):
return self.__repr__()
def __repr__(self):
return "ScriptError [Line %s]: %s" % (self.line, self.message)
class EnvironmentBuilder(object):
"""
Builds an execution environment for a cadquery script.
The environment includes the builtins, as well as
the other methods the script will need.
"""
def __init__(self):
self.env = {}
def with_real_builtins(self):
return self.with_builtins(__builtins__)
def with_builtins(self, env_dict):
self.env['__builtins__'] = env_dict
return self
def with_cadquery_objects(self):
self.env['cadquery'] = cadquery
self.env['cq'] = cadquery
return self
def add_entry(self, name, value):
self.env[name] = value
return self
def build(self):
return self.env
class ParameterDescriptionFinder(ast.NodeTransformer):
"""
Visits a parse tree, looking for function calls to describe_parameter(var, description )
"""
def __init__(self, cq_model):
self.cqModel = cq_model
def visit_Call(self,node):
"""
Called when we see a function call. Is it describe_parameter?
"""
try:
if node.func.id == 'describe_parameter':
#looks like we have a call to our function.
#first parameter is the variable,
#second is the description
varname = node.args[0].id
desc = node.args[1].s
self.cqModel.add_parameter_description(varname,desc)
except:
print "Unable to handle function call"
pass
return node
class ConstantAssignmentFinder(ast.NodeTransformer):
"""
Visits a parse tree, and adds script parameters to the cqModel
"""
def __init__(self, cq_model):
self.cqModel = cq_model
def handle_assignment(self, var_name, value_node):
try:
if type(value_node) == ast.Num:
self.cqModel.add_script_parameter(
InputParameter.create(value_node, var_name, NumberParameterType, value_node.n))
elif type(value_node) == ast.Str:
self.cqModel.add_script_parameter(
InputParameter.create(value_node, var_name, StringParameterType, value_node.s))
elif type(value_node == ast.Name):
if value_node.id == 'True':
self.cqModel.add_script_parameter(
InputParameter.create(value_node, var_name, BooleanParameterType, True))
elif value_node.id == 'False':
self.cqModel.add_script_parameter(
InputParameter.create(value_node, var_name, BooleanParameterType, True))
except:
print "Unable to handle assignment for variable '%s'" % var_name
pass
def visit_Assign(self, node):
try:
left_side = node.targets[0]
#do not handle attribute assignments
if isinstance(left_side,ast.Attribute):
return
if type(node.value) in [ast.Num, ast.Str, ast.Name]:
self.handle_assignment(left_side.id, node.value)
elif type(node.value) == ast.Tuple:
# we have a multi-value assignment
for n, v in zip(left_side.elts, node.value.elts):
self.handle_assignment(n.id, v)
except:
traceback.print_exc()
print "Unable to handle assignment for node '%s'" % ast.dump(left_side)
return node