config.yml example,
DBtables:
CurrentMinuteLoad:
CSV_File: trend.csv
Table_Name: currentminuteload
GUI image,
This may not be the cleanest route to take.
I'm making a GUI that creates a config.yml file for another python script I'm working with.
Using pysimplegui, My button isn't functioning the way I'd expect it to. It currently and accurately checks for the Reference name (example here would be CurrentMinuteLoad) and will kick it back if it exists, but will skip the check for the table (so the ELIF statement gets skipped). Adding the table still works, I'm just not getting the double-check that I want. Also, I have to hit the Okay button twice in the GUI for it to work?? A weird quirk that doesn't quite make sense to me.
def add_table():
window2.read()
with open ("config.yml","r") as h:
if values['new_ref'] in h.read():
sg.popup('Reference name already exists')
elif values['new_db'] in h.read():
sg.popup('Table name already exists')
else:
with open("config.yml", "a+") as f:
f.write("\n " + values['new_ref'] +":")
f.write("\n CSV_File:" + values['new_csv'])
f.write("\n Table_Name:" + values['new_db'])
f.close()
sg.popup('The reference "' + values['new_ref'] + '" has been included and will add the table "' + values['new_db'] + '" to PG Admin during the next scheduled upload')
When you use h.read(), you should save the value since it will read it like a stream, and subsequent calls for this method will result in an empty string.
Try editing the code like this:
with open ("config.yml","r") as h:
content = h.read()
if values['new_ref'] in content:
sg.popup('Reference name already exists')
elif values['new_db'] in content:
sg.popup('Table name already exists')
else:
# ...
You should update the YAML file using a real YAML parser, that will allow you
to check on duplicate values, without using in, which will give you false
positives when a new value is a substring of an existing value (or key).
In the following I add values twice, and show the resulting YAML. The
first time around the check on new_ref and new_db does not find
a match although it is a substring of existing values. The second time
using the same values there is of course a match on the previously added
values.
import sys
import ruamel.yaml
from pathlib import Path
def add_table(filename, values, verbose=False):
error = False
yaml = ruamel.yaml.YAML()
data = yaml.load(filename)
dbtables = data['DBtables']
if values['new_ref'] in dbtables:
print(f'Reference name "{values["new_ref"]}" already exists') # use sg.popup in your code
error = True
for k, v in dbtables.items():
if values['new_db'] in v.values():
print(f'Table name "{values["new_db"]}" already exists')
error = True
if error:
return
dbtables[values['new_ref']] = d = {}
for x in ['new_cv', 'new_db']:
d[x] = values[x]
yaml.dump(data, filename)
if verbose:
sys.stdout.write(filename.read_text())
values = dict(new_ref='CurrentMinuteL', new_cv='trend_csv', new_db='currentminutel')
add_table(Path('config.yaml'), values, verbose=True)
print('========')
add_table(Path('config.yaml'), values, verbose=True)
which gives:
DBtables:
CurrentMinuteLoad:
CSV_File: trend.csv
Table_Name: currentminuteload
CurrentMinuteL:
new_cv: trend_csv
new_db: currentminutel
========
Reference name "CurrentMinuteL" already exists
Table name "currentminutel" already exists
How can I get the comments when I iterate through the YAML object
yaml = YAML()
with open(path, 'r') as f:
yaml_data = yaml.load(f)
for obj in yaml_data:
# how to get the comments here?
This is the source data (an ansible playbook)
---
- name: gather all complex custom facts using the custom module
hosts: switches
gather_facts: False
connection: local
tasks:
# There is a bug in ansible 2.4.1 which prevents it loading
# playbook/group_vars
- name: ensure we're running a known working version
assert:
that:
- 'ansible_version.major == 2'
- 'ansible_version.minor == 4'
After Anthon comments, this is the way I found to access the comments in the child nodes (needs to be refined):
for idx, obj in enumerate(yaml_data):
for i, item in enumerate(obj.items()):
pprint(yaml_data[i].ca.items)
You did not specify your input, but since your code expects an obj and
not a key, I assume the root level of your YAML is a sequence and not mapping.
If you want to get the comments after each element (i.e nr 1 and the last) you can do:
import ruamel.yaml
yaml_str = """\
- one # nr 1
- two
- three # the last
"""
yaml = ruamel.yaml.YAML()
data = yaml.load(yaml_str)
for idx, obj in enumerate(data):
comment_token = data.ca.items.get(idx)
if comment_token is None:
continue
print(repr(comment_token[0].value))
which gives:
'# nr 1\n'
'# the last\n'
You might want to strip of the leading octothorpe and trailing newline.
Please note that this works with the current version (0.15.61), but
there is no guarantee it might not to change.
Using the example from Anthon as well as an issue in ruamel.yaml on sourceforge, here's a set of methods which should allow you to retrieve (almost - see below) all the comments in your documents:
from ruamel.yaml import YAML
from ruamel.yaml.comments import CommentedMap, CommentedSeq
# set attributes
def get_comments_map(self, key):
coms = []
comments = self.ca.items.get(key)
if comments is None:
return coms
for token in comments:
if token is None:
continue
elif isinstance(token, list):
coms.extend(token)
else:
coms.append(token)
return coms
def get_comments_seq(self, idx):
coms = []
comments = self.ca.items.get(idx)
if comments is None:
return coms
for token in comments:
if token is None:
continue
elif isinstance(token, list):
coms.extend(token)
else:
coms.append(token)
return coms
setattr(CommentedMap, 'get_comments', get_comments_map)
setattr(CommentedSeq, 'get_comments', get_comments_seq)
# load string
yaml_str = """\
- name: gather all complex custom facts using the custom module
hosts: switches
gather_facts: False
connection: local
tasks:
# There is a bug in ansible 2.4.1 which prevents it loading
# playbook/group_vars
- name: ensure we're running a known working version
assert:
that:
- 'ansible_version.major == 2'
- 'ansible_version.minor == 4'
"""
yml = YAML(typ='rt')
data = yml.load(yaml_str)
def walk_data(data):
if isinstance(data, CommentedMap):
for k, v in data.items():
print(k, [ comment.value for comment in data.get_comments(k)])
if isinstance(v, CommentedMap) or isinstance(v, CommentedSeq):
walk_data(v)
elif isinstance(data, CommentedSeq):
for idx, item in enumerate(data):
print(idx, [ comment.value for comment in data.get_comments(idx)])
if isinstance(item, CommentedMap) or isinstance(item, CommentedSeq):
walk_data(item)
walk_data(data)
Here's the output:
0 []
name []
hosts []
gather_facts []
connection []
tasks ['# There is a bug in ansible 2.4.1 which prevents it loading\n', '# playbook/group_vars\n']
0 []
name []
assert []
that []
0 []
1 []
Unfortunately, there are two is one problems that I have encountered which are not covered by this method:
You will notice that there is no leading \n in the comments for tasks. As a result, it is not possible with this method to differentiate between comments which start on the same line as tasks or on the next line. Since the CommentToken.start_mark.line only contains the absolute line of the comment, it might be able to be compared to the line of tasks. But, I have not yet found a way to retrieve the line associated with tasks inside the loaded data.
There does not seem to be a way that I have found yet to retrieve comments at the head of the document. So, any initial comments would need to be discovered using a method other than to retrieve them outside the yaml reader. But, related to problem #1, these head comments are included in the absolute line count of other comments. To add the comments at the head of the document, you need to use [comment.value for comment in data.ca.comment[1] as per this explanation by Anthon.
I have a python script that calls a system program and reads the output from a file out.txt, acts on that output, and loops. However, it doesn't work, and a close investigation showed that the python script just opens out.txt once and then keeps on reading from that old copy. How can I make the python script reread the file on each iteration? I saw a similar question here on SO but it was about a python script running alongside a program, not calling it, and the solution doesn't work. I tried closing the file before looping back but it didn't do anything.
EDIT:
I already tried closing and opening, it didn't work. Here's the code:
import subprocess, os, sys
filename = sys.argv[1]
file = open(filename,'r')
foo = open('foo','w')
foo.write(file.read().rstrip())
foo = open('foo','a')
crap = open(os.devnull,'wb')
numSolutions = 0
while True:
subprocess.call(["minisat", "foo", "out"], stdout=crap,stderr=crap)
out = open('out','r')
if out.readline().rstrip() == "SAT":
numSolutions += 1
clause = out.readline().rstrip()
clause = clause.split(" ")
print clause
clause = map(int,clause)
clause = map(lambda x: -x,clause)
output = ' '.join(map(lambda x: str(x),clause))
print output
foo.write('\n'+output)
out.close()
else:
break
print "There are ", numSolutions, " solutions."
You need to flush foo so that the external program can see its latest changes. When you write to a file, the data is buffered in the local process and sent to the system in larger blocks. This is done because updating the system file is relatively expensive. In your case, you need to force a flush of the data so that minisat can see it.
foo.write('\n'+output)
foo.flush()
I rewrote it to hopefully be a bit easier to understand:
import os
from shutil import copyfile
import subprocess
import sys
TEMP_CNF = "tmp.in"
TEMP_SOL = "tmp.out"
NULL = open(os.devnull, "wb")
def all_solutions(cnf_fname):
"""
Given a file containing a set of constraints,
generate all possible solutions.
"""
# make a copy of original input file
copyfile(cnf_fname, TEMP_CNF)
while True:
# run minisat to solve the constraint problem
subprocess.call(["minisat", TEMP_CNF, TEMP_SOL], stdout=NULL,stderr=NULL)
# look at the result
with open(TEMP_SOL) as result:
line = next(result)
if line.startswith("SAT"):
# Success - return solution
line = next(result)
solution = [int(i) for i in line.split()]
yield solution
else:
# Failure - no more solutions possible
break
# disqualify found solution
with open(TEMP_CNF, "a") as constraints:
new_constraint = " ".join(str(-i) for i in sol)
constraints.write("\n")
constraints.write(new_constraint)
def main(cnf_fname):
"""
Given a file containing a set of constraints,
count the possible solutions.
"""
count = sum(1 for i in all_solutions(cnf_fname))
print("There are {} solutions.".format(count))
if __name__=="__main__":
if len(sys.argv) == 2:
main(sys.argv[1])
else:
print("Usage: {} cnf.in".format(sys.argv[0]))
You take your file_var and end the loop with file_var.close().
for ... :
ga_file = open(out.txt, 'r')
... do stuff
ga_file.close()
Demo of an implementation below (as simple as possible, this is all of the Jython code needed)...
__author__ = ''
import time
var = 'false'
while var == 'false':
out = open('out.txt', 'r')
content = out.read()
time.sleep(3)
print content
out.close()
generates this output:
2015-01-09, 'stuff added'
2015-01-09, 'stuff added' # <-- this is when i just saved my update
2015-01-10, 'stuff added again :)' # <-- my new output from file reads
I strongly recommend reading the error messages. They hold quite a lot of information.
I think the full file name should be written for debug purposes.
I'm trying to compare a csv file containing required Linux packages with the current installed packages. The comparison should output any packages not installed or newer than the current installed packages.
The problem is that I'm unable to loop through the list of installed packages and show all hits, for instance packages with the same name and version, but different architecture should be shown twice(for instance compat-libstdc++-33), but I only getting the first hit with the script below.
#!/usr/bin/python
import rpm
import csv
import sys
import os
'''
Script to check installed rpms against a csv file containing the package name and version similar to the list below:
atk,1.12.2
libart_lgpl,2.3
info,4.9
libsepol,1.15.2
libusb,0.1.12
libfontenc,1.4.2
'''
if len(sys.argv) !=2:
print ''
print 'Usage: ', sys.argv[0], '/path/to/csv_input_file'
print ''
sys.exit(1)
if not os.path.isfile(sys.argv[1]):
print ''
print sys.argv[1], 'not found!'
print ''
sys.exit(1)
else:
input_csv = sys.argv[1]
pkgRequired = csv.reader(open(input_csv),delimiter=',')
pkgInstalledName = []
pkgInstalledVersion = []
pkgInstalledArch = []
ts = rpm.TransactionSet()
mi = ts.dbMatch()
for h in mi:
pkgInstalledName.append((h['name']))
pkgInstalledVersion.append((h['version']))
pkgInstalledArch.append((h['arch']))
for row in pkgRequired:
pkgRequiredName = row[0]
pkgRequiredVersion = row[1]
#pkgRequiredArch = row[2]
if pkgRequiredName in pkgInstalledName:
if pkgInstalledVersion[pkgInstalledName.index(pkgRequiredName)] >= pkgRequiredVersion:
pass
else:
print '\nInstalled: ',pkgInstalledName[pkgInstalledName.index(pkgRequiredName)], pkgInstalledVersion[pkgInstalledName.index(pkgRequiredName)], pkgInstalledArch[pkgInstalledName.index(pkgRequiredName)], ' \nRequired: ', ' ', pkgRequiredName,pkgRequiredVersion
Assuming that there's no problem with the way that you're reading the list of installed packages (I'm not familiar with the rpm module), then your only problem is with using the index() function. This function return the first occurrence of an item with the specified value - and it isn't what you want.
A correct implementation (which is also much more efficient) would be:
installedPackages = {} #create a hash table, mapping package names to LISTS of installed package versions and architectures
for h in mi:
l = installedPackages.get(h['name'], list()) #return either the existing list, or a new one if this is the first time that the name appears.
l.append( (h['version'], h['arch']) )
...
if requiredPackageName in installedPackages:
for ver, arch in installedPackages[requiredPackageName]: print ...
This is what I ended up doing to get this working. The script currently is not checking for the architecture of required packages, but at least it shows the arch installed. The script works (as far as I know) but can be improved as its my first at python :)
#!/usr/bin/python
import rpm
import csv
import sys
import os
'''
Script to check installed rpms against a csv file containing the package name and version similar to the list below:
atk,1.12.2
libart_lgpl,2.3
info,4.9
libsepol,1.15.2
libusb,0.1.12
libfontenc,1.4.2
'''
#silverbullet - 20120301
if len(sys.argv) !=2:
print ''
print 'Usage: ', sys.argv[0], '/path/to/csv_input_file'
print ''
sys.exit(1)
if not os.path.isfile(sys.argv[1]):
print ''
print sys.argv[1], 'not found!'
print ''
sys.exit(1)
else:
input_csv = sys.argv[1]
pkgRequired = csv.reader(open(input_csv),delimiter=',')
pkgInstalledName = []
pkgInstalledVersion = []
pkgInstalledArch = []
ts = rpm.TransactionSet()
mi = ts.dbMatch()
for h in mi:
pkgInstalledName.append((h['name']))
pkgInstalledVersion.append((h['version']))
pkgInstalledArch.append((h['arch']))
for row in pkgRequired:
try:
pkgRequiredName = row[0]
pkgRequiredVersion = row[1]
#pkgRequiredArch = row[2] - This is not implemented yet, ie, script will ignore architecture in csv input file
except:
print "Unexpected Error. Check if input is csv format with no blank lines. "#, sys.exc_info()[1]
break
else:
for pos, pkg in enumerate(pkgInstalledName):
if pkg == pkgRequiredName:
if pkgInstalledVersion[pos] >= pkgRequiredVersion:
pass
else:
print '\nInstalled:', pkgInstalledName[pos], pkgInstalledVersion[pos], pkgInstalledArch[pos], '\nRequired: ', pkg, pkgRequiredVersion
I'm trying to read the target file/directory of a shortcut (.lnk) file from Python. Is there a headache-free way to do it? The spec is way over my head.
I don't mind using Windows-only APIs.
My ultimate goal is to find the "(My) Videos" folder on Windows XP and Vista. On XP, by default, it's at %HOMEPATH%\My Documents\My Videos, and on Vista it's %HOMEPATH%\Videos. However, the user can relocate this folder. In the case, the %HOMEPATH%\Videos folder ceases to exists and is replaced by %HOMEPATH%\Videos.lnk which points to the new "My Videos" folder. And I want its absolute location.
Create a shortcut using Python (via WSH)
import sys
import win32com.client
shell = win32com.client.Dispatch("WScript.Shell")
shortcut = shell.CreateShortCut("t:\\test.lnk")
shortcut.Targetpath = "t:\\ftemp"
shortcut.save()
Read the Target of a Shortcut using Python (via WSH)
import sys
import win32com.client
shell = win32com.client.Dispatch("WScript.Shell")
shortcut = shell.CreateShortCut("t:\\test.lnk")
print(shortcut.Targetpath)
I know this is an older thread but I feel that there isn't much information on the method that uses the link specification as noted in the original question.
My shortcut target implementation could not use the win32com module and after a lot of searching, decided to come up with my own. Nothing else seemed to accomplish what I needed under my restrictions. Hopefully this will help other folks in this same situation.
It uses the binary structure Microsoft has provided for MS-SHLLINK.
import struct
path = 'myfile.txt.lnk'
target = ''
with open(path, 'rb') as stream:
content = stream.read()
# skip first 20 bytes (HeaderSize and LinkCLSID)
# read the LinkFlags structure (4 bytes)
lflags = struct.unpack('I', content[0x14:0x18])[0]
position = 0x18
# if the HasLinkTargetIDList bit is set then skip the stored IDList
# structure and header
if (lflags & 0x01) == 1:
position = struct.unpack('H', content[0x4C:0x4E])[0] + 0x4E
last_pos = position
position += 0x04
# get how long the file information is (LinkInfoSize)
length = struct.unpack('I', content[last_pos:position])[0]
# skip 12 bytes (LinkInfoHeaderSize, LinkInfoFlags, and VolumeIDOffset)
position += 0x0C
# go to the LocalBasePath position
lbpos = struct.unpack('I', content[position:position+0x04])[0]
position = last_pos + lbpos
# read the string at the given position of the determined length
size= (length + last_pos) - position - 0x02
temp = struct.unpack('c' * size, content[position:position+size])
target = ''.join([chr(ord(a)) for a in temp])
Alternatively, you could try using SHGetFolderPath(). The following code might work, but I'm not on a Windows machine right now so I can't test it.
import ctypes
shell32 = ctypes.windll.shell32
# allocate MAX_PATH bytes in buffer
video_folder_path = ctypes.create_string_buffer(260)
# 0xE is CSIDL_MYVIDEO
# 0 is SHGFP_TYPE_CURRENT
# If you want a Unicode path, use SHGetFolderPathW instead
if shell32.SHGetFolderPathA(None, 0xE, None, 0, video_folder_path) >= 0:
# success, video_folder_path now contains the correct path
else:
# error
Basically call the Windows API directly. Here is a good example found after Googling:
import os, sys
import pythoncom
from win32com.shell import shell, shellcon
shortcut = pythoncom.CoCreateInstance (
shell.CLSID_ShellLink,
None,
pythoncom.CLSCTX_INPROC_SERVER,
shell.IID_IShellLink
)
desktop_path = shell.SHGetFolderPath (0, shellcon.CSIDL_DESKTOP, 0, 0)
shortcut_path = os.path.join (desktop_path, "python.lnk")
persist_file = shortcut.QueryInterface (pythoncom.IID_IPersistFile)
persist_file.Load (shortcut_path)
shortcut.SetDescription ("Updated Python %s" % sys.version)
mydocs_path = shell.SHGetFolderPath (0, shellcon.CSIDL_PERSONAL, 0, 0)
shortcut.SetWorkingDirectory (mydocs_path)
persist_file.Save (shortcut_path, 0)
This is from http://timgolden.me.uk/python/win32_how_do_i/create-a-shortcut.html.
You can search for "python ishelllink" for other examples.
Also, the API reference helps too: http://msdn.microsoft.com/en-us/library/bb774950(VS.85).aspx
I also realize this question is old, but I found the answers to be most relevant to my situation.
Like Jared's answer, I also could not use the win32com module. So Jared's use of the binary structure from MS-SHLLINK got me part of the way there. I needed read shortcuts on both Windows and Linux, where the shortcuts are created on a samba share by Windows. Jared's implementation didn't quite work for me, I think only because I encountered some different variations on the shortcut format. But, it gave me the start I needed (thanks Jared).
So, here is a class named MSShortcut which expands on Jared's approach. However, the implementation is only Python3.4 and above, due to using some pathlib features added in Python3.4
#!/usr/bin/python3
# Link Format from MS: https://msdn.microsoft.com/en-us/library/dd871305.aspx
# Need to be able to read shortcut target from .lnk file on linux or windows.
# Original inspiration from: http://stackoverflow.com/questions/397125/reading-the-target-of-a-lnk-file-in-python
from pathlib import Path, PureWindowsPath
import struct, sys, warnings
if sys.hexversion < 0x03040000:
warnings.warn("'{}' module requires python3.4 version or above".format(__file__), ImportWarning)
# doc says class id =
# 00021401-0000-0000-C000-000000000046
# requiredCLSID = b'\x00\x02\x14\x01\x00\x00\x00\x00\xC0\x00\x00\x00\x00\x00\x00\x46'
# Actually Getting:
requiredCLSID = b'\x01\x14\x02\x00\x00\x00\x00\x00\xC0\x00\x00\x00\x00\x00\x00\x46' # puzzling
class ShortCutError(RuntimeError):
pass
class MSShortcut():
"""
interface to Microsoft Shortcut Objects. Purpose:
- I need to be able to get the target from a samba shared on a linux machine
- Also need to get access from a Windows machine.
- Need to support several forms of the shortcut, as they seem be created differently depending on the
creating machine.
- Included some 'flag' types in external interface to help test differences in shortcut types
Args:
scPath (str): path to shortcut
Limitations:
- There are some omitted object properties in the implementation.
Only implemented / tested enough to recover the shortcut target information. Recognized omissions:
- LinkTargetIDList
- VolumeId structure (if captured later, should be a separate class object to hold info)
- Only captured environment block from extra data
- I don't know how or when some of the shortcut information is used, only captured what I recognized,
so there may be bugs related to use of the information
- NO shortcut update support (though might be nice)
- Implementation requires python 3.4 or greater
- Tested only with Unicode data on a 64bit little endian machine, did not consider potential endian issues
Not Debugged:
- localBasePath - didn't check if parsed correctly or not.
- commonPathSuffix
- commonNetworkRelativeLink
"""
def __init__(self, scPath):
"""
Parse and keep shortcut properties on creation
"""
self.scPath = Path(scPath)
self._clsid = None
self._lnkFlags = None
self._lnkInfoFlags = None
self._localBasePath = None
self._commonPathSuffix = None
self._commonNetworkRelativeLink = None
self._name = None
self._relativePath = None
self._workingDir = None
self._commandLineArgs = None
self._iconLocation = None
self._envTarget = None
self._ParseLnkFile(self.scPath)
#property
def clsid(self):
return self._clsid
#property
def lnkFlags(self):
return self._lnkFlags
#property
def lnkInfoFlags(self):
return self._lnkInfoFlags
#property
def localBasePath(self):
return self._localBasePath
#property
def commonPathSuffix(self):
return self._commonPathSuffix
#property
def commonNetworkRelativeLink(self):
return self._commonNetworkRelativeLink
#property
def name(self):
return self._name
#property
def relativePath(self):
return self._relativePath
#property
def workingDir(self):
return self._workingDir
#property
def commandLineArgs(self):
return self._commandLineArgs
#property
def iconLocation(self):
return self._iconLocation
#property
def envTarget(self):
return self._envTarget
#property
def targetPath(self):
"""
Args:
woAnchor (bool): remove the anchor (\\server\path or drive:) from returned path.
Returns:
a libpath PureWindowsPath object for combined workingDir/relative path
or the envTarget
Raises:
ShortCutError when no target path found in Shortcut
"""
target = None
if self.workingDir:
target = PureWindowsPath(self.workingDir)
if self.relativePath:
target = target / PureWindowsPath(self.relativePath)
else: target = None
if not target and self.envTarget:
target = PureWindowsPath(self.envTarget)
if not target:
raise ShortCutError("Unable to retrieve target path from MS Shortcut: shortcut = {}"
.format(str(self.scPath)))
return target
#property
def targetPathWOAnchor(self):
tp = self.targetPath
return tp.relative_to(tp.anchor)
def _ParseLnkFile(self, lnkPath):
with lnkPath.open('rb') as f:
content = f.read()
# verify size (4 bytes)
hdrSize = struct.unpack('I', content[0x00:0x04])[0]
if hdrSize != 0x4C:
raise ShortCutError("MS Shortcut HeaderSize = {}, but required to be = {}: shortcut = {}"
.format(hdrSize, 0x4C, str(lnkPath)))
# verify LinkCLSID id (16 bytes)
self._clsid = bytes(struct.unpack('B'*16, content[0x04:0x14]))
if self._clsid != requiredCLSID:
raise ShortCutError("MS Shortcut ClassID = {}, but required to be = {}: shortcut = {}"
.format(self._clsid, requiredCLSID, str(lnkPath)))
# read the LinkFlags structure (4 bytes)
self._lnkFlags = struct.unpack('I', content[0x14:0x18])[0]
#logger.debug("lnkFlags=0x%0.8x" % self._lnkFlags)
position = 0x4C
# if HasLinkTargetIDList bit, then position to skip the stored IDList structure and header
if (self._lnkFlags & 0x01):
idListSize = struct.unpack('H', content[position:position+0x02])[0]
position += idListSize + 2
# if HasLinkInfo, then process the linkinfo structure
if (self._lnkFlags & 0x02):
(linkInfoSize, linkInfoHdrSize, self._linkInfoFlags,
volIdOffset, localBasePathOffset,
cmnNetRelativeLinkOffset, cmnPathSuffixOffset) = struct.unpack('IIIIIII', content[position:position+28])
# check for optional offsets
localBasePathOffsetUnicode = None
cmnPathSuffixOffsetUnicode = None
if linkInfoHdrSize >= 0x24:
(localBasePathOffsetUnicode, cmnPathSuffixOffsetUnicode) = struct.unpack('II', content[position+28:position+36])
#logger.debug("0x%0.8X" % linkInfoSize)
#logger.debug("0x%0.8X" % linkInfoHdrSize)
#logger.debug("0x%0.8X" % self._linkInfoFlags)
#logger.debug("0x%0.8X" % volIdOffset)
#logger.debug("0x%0.8X" % localBasePathOffset)
#logger.debug("0x%0.8X" % cmnNetRelativeLinkOffset)
#logger.debug("0x%0.8X" % cmnPathSuffixOffset)
#logger.debug("0x%0.8X" % localBasePathOffsetUnicode)
#logger.debug("0x%0.8X" % cmnPathSuffixOffsetUnicode)
# if info has a localBasePath
if (self._linkInfoFlags & 0x01):
bpPosition = position + localBasePathOffset
# not debugged - don't know if this works or not
self._localBasePath = UnpackZ('z', content[bpPosition:])[0].decode('ascii')
#logger.debug("localBasePath: {}".format(self._localBasePath))
if localBasePathOffsetUnicode:
bpPosition = position + localBasePathOffsetUnicode
self._localBasePath = UnpackUnicodeZ('z', content[bpPosition:])[0]
self._localBasePath = self._localBasePath.decode('utf-16')
#logger.debug("localBasePathUnicode: {}".format(self._localBasePath))
# get common Path Suffix
cmnSuffixPosition = position + cmnPathSuffixOffset
self._commonPathSuffix = UnpackZ('z', content[cmnSuffixPosition:])[0].decode('ascii')
#logger.debug("commonPathSuffix: {}".format(self._commonPathSuffix))
if cmnPathSuffixOffsetUnicode:
cmnSuffixPosition = position + cmnPathSuffixOffsetUnicode
self._commonPathSuffix = UnpackUnicodeZ('z', content[cmnSuffixPosition:])[0]
self._commonPathSuffix = self._commonPathSuffix.decode('utf-16')
#logger.debug("commonPathSuffix: {}".format(self._commonPathSuffix))
# check for CommonNetworkRelativeLink
if (self._linkInfoFlags & 0x02):
relPosition = position + cmnNetRelativeLinkOffset
self._commonNetworkRelativeLink = CommonNetworkRelativeLink(content, relPosition)
position += linkInfoSize
# If HasName
if (self._lnkFlags & 0x04):
(position, self._name) = self.readStringObj(content, position)
#logger.debug("name: {}".format(self._name))
# get relative path string
if (self._lnkFlags & 0x08):
(position, self._relativePath) = self.readStringObj(content, position)
#logger.debug("relPath='{}'".format(self._relativePath))
# get working dir string
if (self._lnkFlags & 0x10):
(position, self._workingDir) = self.readStringObj(content, position)
#logger.debug("workingDir='{}'".format(self._workingDir))
# get command line arguments
if (self._lnkFlags & 0x20):
(position, self._commandLineArgs) = self.readStringObj(content, position)
#logger.debug("commandLineArgs='{}'".format(self._commandLineArgs))
# get icon location
if (self._lnkFlags & 0x40):
(position, self._iconLocation) = self.readStringObj(content, position)
#logger.debug("iconLocation='{}'".format(self._iconLocation))
# look for environment properties
if (self._lnkFlags & 0x200):
while True:
size = struct.unpack('I', content[position:position+4])[0]
#logger.debug("blksize=%d" % size)
if size==0: break
signature = struct.unpack('I', content[position+4:position+8])[0]
#logger.debug("signature=0x%0.8x" % signature)
# EnvironmentVariableDataBlock
if signature == 0xA0000001:
if (self._lnkFlags & 0x80): # unicode
self._envTarget = UnpackUnicodeZ('z', content[position+268:])[0]
self._envTarget = self._envTarget.decode('utf-16')
else:
self._envTarget = UnpackZ('z', content[position+8:])[0].decode('ascii')
#logger.debug("envTarget='{}'".format(self._envTarget))
position += size
def readStringObj(self, scContent, position):
"""
returns:
tuple: (newPosition, string)
"""
strg = ''
size = struct.unpack('H', scContent[position:position+2])[0]
#logger.debug("workingDirSize={}".format(size))
if (self._lnkFlags & 0x80): # unicode
size *= 2
strg = struct.unpack(str(size)+'s', scContent[position+2:position+2+size])[0]
strg = strg.decode('utf-16')
else:
strg = struct.unpack(str(size)+'s', scContent[position+2:position+2+size])[0].decode('ascii')
#logger.debug("strg='{}'".format(strg))
position += size + 2 # 2 bytes to account for CountCharacters field
return (position, strg)
class CommonNetworkRelativeLink():
def __init__(self, scContent, linkContentPos):
self._networkProviderType = None
self._deviceName = None
self._netName = None
(linkSize, flags, netNameOffset,
devNameOffset, self._networkProviderType) = struct.unpack('IIIII', scContent[linkContentPos:linkContentPos+20])
#logger.debug("netnameOffset = {}".format(netNameOffset))
if netNameOffset > 0x014:
(netNameOffsetUnicode, devNameOffsetUnicode) = struct.unpack('II', scContent[linkContentPos+20:linkContentPos+28])
#logger.debug("netnameOffsetUnicode = {}".format(netNameOffsetUnicode))
self._netName = UnpackUnicodeZ('z', scContent[linkContentPos+netNameOffsetUnicode:])[0]
self._netName = self._netName.decode('utf-16')
self._deviceName = UnpackUnicodeZ('z', scContent[linkContentPos+devNameOffsetUnicode:])[0]
self._deviceName = self._deviceName.decode('utf-16')
else:
self._netName = UnpackZ('z', scContent[linkContentPos+netNameOffset:])[0].decode('ascii')
self._deviceName = UnpackZ('z', scContent[linkContentPos+devNameOffset:])[0].decode('ascii')
#property
def deviceName(self):
return self._deviceName
#property
def netName(self):
return self._netName
#property
def networkProviderType(self):
return self._networkProviderType
def UnpackZ (fmt, buf) :
"""
Unpack Null Terminated String
"""
#logger.debug(bytes(buf))
while True :
pos = fmt.find ('z')
if pos < 0 :
break
z_start = struct.calcsize (fmt[:pos])
z_len = buf[z_start:].find(b'\0')
#logger.debug(z_len)
fmt = '%s%dsx%s' % (fmt[:pos], z_len, fmt[pos+1:])
#logger.debug("fmt='{}', len={}".format(fmt, z_len))
fmtlen = struct.calcsize(fmt)
return struct.unpack (fmt, buf[0:fmtlen])
def UnpackUnicodeZ (fmt, buf) :
"""
Unpack Null Terminated String
"""
#logger.debug(bytes(buf))
while True :
pos = fmt.find ('z')
if pos < 0 :
break
z_start = struct.calcsize (fmt[:pos])
# look for null bytes by pairs
z_len = 0
for i in range(z_start,len(buf),2):
if buf[i:i+2] == b'\0\0':
z_len = i-z_start
break
fmt = '%s%dsxx%s' % (fmt[:pos], z_len, fmt[pos+1:])
# logger.debug("fmt='{}', len={}".format(fmt, z_len))
fmtlen = struct.calcsize(fmt)
return struct.unpack (fmt, buf[0:fmtlen])
I hope this helps others as well.
Thanks
I didn't really like any of the answers available because I didn't want to keep importing more and more libraries and the 'shell' option was spotty on my test machines. I opted for reading the ".lnk" in and then using a regular expression to read out the path. For my purposes, I am looking for pdf files that were recently opened and then reading the content of those files:
# Example file path to the shortcut
shortcut = "shortcutFileName.lnk"
# Open the lnk file using the ISO-8859-1 encoder to avoid errors for special characters
lnkFile = open(shortcut, 'r', encoding = "ISO-8859-1")
# Use a regular expression to parse out the pdf file on C:\
filePath = re.findall("C:.*?pdf", lnkFile.read(), flags=re.DOTALL)
# Close File
lnkFile.close()
# Read the pdf at the lnk Target
pdfFile = open(tmpFilePath[0], 'rb')
Comments:
Obviously this works for pdf but needs to specify other file extensions accordingly.
It's easy as opening ".exe" file. Here also, we are going to use the os module for this. You just have to create a shortcut .lnk and store it in any folder of your choice. Then, in any Python file, first import the os module (already installed, just import). Then, use a variable, say path, and assign it a string value containing the location of your .lnk file. Just create a shortcut of your desired application. At last, we will use os.startfile()
to open our shortcut.
Points to remember:
The location should be within double inverted commas.
Most important, open Properties. Then, under that, open "Details". There, you can get the exact name of your shortcut. Please write that name with ".lnk" at last.
Now, you have completed the procedure. I hope it helps you. For additional assistance, I am leaving my code for this at the bottom.
import os
path = "C:\\Users\\hello\\OneDrive\\Desktop\\Shortcuts\\OneNote for Windows 10.lnk"
os.startfile(path)
In my code, I used path as variable and I had created a shortcut for OneNote. In path, I defined the location of OneNote's shortcut. So when I use os.startfile(path), the os module is going to open my shortcut file defined in variable path.
this job is possible without any modules, doing this will return a b string having the destination of the shortcut file. Basically what you do is you open the file in read binary mode (rb mode). This is the code to accomplish this task:
with open('programs.lnk - Copy','rb') as f:
destination=f.read()
i am currently using python 3.9.2, in case you face problems with this, just tell me and i will try to fix it.
A more stable solution in python, using powershell to read the target path from the .lnk file.
using only standard libraries avoids introducing extra dependencies such as win32com
this approach works with the .lnks that failed with jared's answer, more details
we avoid directly reading the file, which felt hacky, and sometimes failed
import subprocess
def get_target(link_path) -> (str, str):
"""
Get the target & args of a Windows shortcut (.lnk)
:param link_path: The Path or string-path to the shortcut, e.g. "C:\\Users\\Public\\Desktop\\My Shortcut.lnk"
:return: A tuple of the target and arguments, e.g. ("C:\\Program Files\\My Program.exe", "--my-arg")
"""
# get_target implementation by hannes, https://gist.github.com/Winand/997ed38269e899eb561991a0c663fa49
ps_command = \
"$WSShell = New-Object -ComObject Wscript.Shell;" \
"$Shortcut = $WSShell.CreateShortcut(\"" + str(link_path) + "\"); " \
"Write-Host $Shortcut.TargetPath ';' $shortcut.Arguments "
output = subprocess.run(["powershell.exe", ps_command], capture_output=True)
raw = output.stdout.decode('utf-8')
launch_path, args = [x.strip() for x in raw.split(';', 1)]
return launch_path, args
# to test
shortcut_file = r"C:\Users\REPLACE_WITH_USERNAME\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Accessibility\Narrator.lnk"
a, args = get_target(shortcut_file)
print(a) # C:\WINDOWS\system32\narrator.exe
(you can remove -> typehinting to get it to work in older python versions)
I did notice this is slow when running on lots of shortcuts. You could use jareds method, check if the result is None, and if so, run this code to get the target path.
The nice approach with direct regex-based parsing (proposed in the answer) didn't work reliable for all shortcuts in my case. Some of them have only relative path like ..\\..\\..\\..\\..\\..\\Program Files\\ImageGlass\\ImageGlass.exe (produced by msi-installer), and it is stored with wide chars, which are tricky to handle in Python.
So I've discovered a Python module LnkParse3, which is easy to use and meets my needs.
Here is a sample script to show target of a lnk-file passed as first argument:
import LnkParse3
import sys
with open(sys.argv[1], 'rb') as indata:
lnk = LnkParse3.lnk_file(indata)
print(lnk.lnk_command)
I arrived at this thread looking for a way to parse a ".lnk" file and get the target file name.
I found another very simple solution:
pip install comtypes
Then
from comtypes.client import CreateObject
from comtypes.persist import IPersistFile
from comtypes.shelllink import ShellLink
# MAKE SURE THIS VAT CONTAINS A STRING AND NOT AN OBJECT OF 'PATH'
# I spent too much time figuring out the problem with .load(..) function ahead
pathStr="c:\folder\yourlink.lnk"
s = CreateObject(ShellLink)
p = s.QueryInterface(IPersistFile)
p.Load(pathStr, False)
print(s.GetPath())
print(s.GetArguments())
print(s.GetWorkingDirectory())
print(s.GetIconLocation())
try:
# the GetDescription create exception in some of the links
print(s.GetDescription())
except Exception as e:
print(e)
print(s.Hotkey)
print(s.ShowCmd)
Based on this great answer...
https://stackoverflow.com/a/43856809/2992810