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mirror of https://github.com/instaloader/instaloader.git synced 2024-08-17 12:19:38 +02:00

Evaluate --only-if filter smarter

If --only-if='likes>1000 or viewer_has_liked' is given, it is not
neccessary to evaluate viewer_has_liked if the post has more than 1000
likes. The new implementation smartly handles this case.
This commit is contained in:
Alexander Graf 2017-08-23 15:33:35 +02:00
parent ce38f5880f
commit 8cf1997460

View File

@ -2,7 +2,6 @@
"""Download pictures (or videos) along with their captions and other metadata from Instagram."""
import ast
import copy
import getpass
import json
import os
@ -132,35 +131,29 @@ def format_string_contains_key(format_string: str, key: str) -> bool:
def filterstr_to_filterfunc(filter_str: str, logged_in: bool) -> Callable[['Post'], bool]:
"""Takes an --only-if=... filter specification and makes a filter_func Callable out of it."""
class VerifyFilter(ast.NodeVisitor):
# The filter_str is parsed, then all names occurring in its AST are replaced by loads to post.<name>. A
# function Post->bool is returned which evaluates the filter with the post as 'post' in its namespace.
class TransformFilterAst(ast.NodeTransformer):
def visit_Name(self, node: ast.Name):
# pylint:disable=invalid-name
# pylint:disable=invalid-name,no-self-use
if not isinstance(node.ctx, ast.Load):
raise InvalidArgumentException("Invalid filter: Modifying variables ({}) not allowed.".format(node.id))
if not hasattr(Post, node.id):
raise InvalidArgumentException("Invalid filter: Name {} is not defined.".format(node.id))
if node.id in Post.LOGIN_REQUIRING_PROPERTIES and not logged_in:
raise InvalidArgumentException("Invalid filter: Name {} requires being logged in.".format(node.id))
return self.generic_visit(node)
new_node = ast.Attribute(ast.copy_location(ast.Name('post', ast.Load()), node), node.id,
ast.copy_location(ast.Load(), node))
return ast.copy_location(new_node, node)
filter_ast = ast.parse(filter_str, filename='<--only-if parameter>', mode='eval')
VerifyFilter().visit(filter_ast)
input_filename = '<--only-if parameter>'
compiled_filter = compile(TransformFilterAst().visit(ast.parse(filter_str, filename=input_filename, mode='eval')),
filename=input_filename, mode='eval')
def filterfunc(post: 'Post') -> bool:
class EvaluatePostAttributes(ast.NodeTransformer):
def visit_Name(self, node: ast.Name):
# pylint:disable=invalid-name,no-self-use
obj = post.__getattribute__(node.id)
if isinstance(obj, str):
new_node = ast.Str(obj)
elif isinstance(obj, int) and not isinstance(obj, bool):
new_node = ast.Num(obj)
else: # True, False or None
new_node = ast.NameConstant(obj)
return ast.copy_location(new_node, node)
ast_obj = EvaluatePostAttributes().visit(copy.deepcopy(filter_ast))
# pylint:disable=eval-used
return bool(eval(compile(ast_obj, '', 'eval'), {}))
return bool(eval(compiled_filter, {'post': post}))
return filterfunc