Will we need to create separate unit tests for this issue? A subreddit for all questions related to programming in any language. You can create temporary files which has a visible name on the file system which can be accessed via the name property. tempfile NamedTemporaryFile in Python: Create (and write to a) known, persistent temporary file. delete=True # delete after file closed, current behavior by a job object). I will give it a try. It takes a delete parameter which we can set as False to prevent the file from being deleted when it is closed. somone can come up with a single, concrete suggestion. To view the purposes they believe they have legitimate interest for, or to object to this data processing use the vendor list link below. You can create temporary files which has a visible name on the file system which can be accessed via the name property. delete_on_close=False violates that expectation. def project_to_header(fitsfile, header, use_montage=True, quiet=True, **kwargs): """ Light wrapper of montage with hcongrid as a backup Parameters ----- fitsfile : string a FITS file name header : pyfits.Header A pyfits Header instance with valid WCS to project to use_montage : bool Use montage or hcongrid (scipy's map_coordinates) quiet : bool Silence Montage's output Returns ----- np.ndarray . On 4/11/2021 3:51 PM, Jason R. Coombs wrote: Jason R. Coombs jaraco@jaraco.com added the comment: At least I and Ethan and Martin have expressed a desire for the Tim Golden, Programming . The context manager doesn't care about the NamedTemporaryFile, it's just opening the s3_zip and by the looks of it extracting a file name that you've specified in pq_path to a directory derived for your os.path.dirname It goes hand in hand with the decision to stop using O_TEMPORARY in NamedTemporaryFile(). By voting up you can indicate which examples are most useful and appropriate. Alternatively, it could be that because the file is still open in Python Windows won't let you open it using another application. To select a long list of files click the first file in the list, press and hold SHIFT, then click the last file . This was still causing some confusion, so I rewrote the section in the Information credits to stackoverflow, stackexchange network and user contributions. Steve also wants O_TEMPORARY to be removed, which doesn't seem controversial among this group of people. 2,000 free sign ups available for the "Automate the My teacher says to stay away from StackOverflow and other First software job after 6 months of self-learning. There is a use case of needing to let another thread or process open the temporary file while in a given context, but ensure that the file is deleted when the context exits. Learn Python Language - paramdescriptionmodemode to open file, default=w+bdeleteTo delete file on closure, default=Truesuffixfilename suffix,. Changed in version 3.8: Added errors parameter. See bpo-14514 for an alternate proposal to solve this. O_TEMPORARY is clearly not the right option here, and we should just move the unlink call into __exit__ and attempt it even if close() has been called. If I've misrepresented anyone's view, please speak up! 'delete' -- whether the file is deleted on close (default True). The fact that it's different on posix (you can open the file for reading by name without closing it first) makes this problem worse. Requiring def save_to_model (file_field, file_name): img_temp = NamedTemporaryFile (delete=True) img_temp.write (open (os.path.join (settings.MEDIA_ROOT, file_name), 'r').read ()) img_temp.flush () file_field.save (os.path.basename (file_name), File (img_temp), save=False) # delete files after saving in models delete_file (file_name) Example #12 0 tf = tempfile.NamedTemporaryFile(delete=False) and then delete the file manually once you've finished viewing it in the other application. The default of privacy statement. The test should conjure up an appropriate file, call the function, check the results, and clean up the file afterwards. Disclaimer: All information is provided as it is with no warranty of any kind. My opinion is that no extra flags are necessary. It doesn't matter when the file gets cleaned up, as long as it is cleaned up "eventually." The default of open mode. registered This approach would allow a user to opt in to the future behavior which has the desired effect of preferring the default behavior (in as little as two releases). The O_TEMPORARY flag is not generally compatible with this use case, since very few programs in Windows share delete access. It would still be essentially useless on Windows, but we maybe don't care about that. Solution 2 In this case, the file will deleted even if the current process crashes or gets terminated (e.g. On Mon, Apr 12, 2021 at 12:51 AM Jason R. Coombs wrote: Jason R. Coombs added the comment: Separately to my previous message. Breaking compatibility is allowed in minor versions (3.11 at this point, as this won't make it in before 3.10 feature freeze). Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state. [1] https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilew#caching_behavior. I agree we need to add something here to better support the idiom where the "close" and "delete" operations on a NamedTemporaryFile are decoupled without the delete becoming a completely independent call to os.unlink(). (In contrast, tempfile.NamedTemporaryFile() provides a 'file' object and deletes the file as soon as that file object is closed, so the temporary file cannot be safely re-opened by another library or process.) "fixing" ;) NamedTemporaryFile was arduous, complicated, or had serious backwards-compatibility issues then I would completely agree with you. Does it get removed inside the context manager of extract_file_from_zip()? If file.close() "offers deterministic resource management," then you have to consider the file's open/closed state to be a resource separate from its existence. PYTHON : How to use tempfile.NamedTemporaryFile()? It is also a bit perverse to have to keep the file open for writing after you're definitively done writing it, just to prevent it from being deleted prematurely. Sign in Clarify the documentation around SQLite and case-sensitive string matching. Press question mark to learn the rest of the keyboard shortcuts. Select the file and press your Delete key, or click Delete on the Home tab of the ribbon. Press and hold the CTRL key as you select multiple files to delete. Note that an internal flag will be needed or mmap its contents, or otherwise access it however you like. from tempfile import namedtemporaryfile # when delete=false is specified, this file will not be # removed from disk automatically upon close/garbage collection f = namedtemporaryfile (delete=false) # save the file path path = f.name # write something to it f.write ('some random data') # you can now close the file and later # open and read it Use them at your own risk. Or can we open *two* file handles at the start, one for writing and one for reading, return the one for writing, and keep the one for reading internal, purely to keep the file locked? Well, fixing NamedTemporaryFile in either of the ways we've discussed isn't going to fix people writing non-portable code. super ( NamedTemporaryFile ,self). default, preferred usage work well in a portable environment. A file that's opened with DELETE access cannot be reopened in most cases, because most opens do not share delete access, but it also can't be closed to allow it to be reopened because the OS will delete it. The file is created securely, using the same rules as mkstemp (). Creates a temporary file, yields its name, and upon context exit, deletes it. After all, you can currently get deterministic cleanup (with a __del__ fallback) via: You need to be careful to make sure you keep the CM alive (or it will delete the file behind your back), but the idiom RDM described in the other issues handles that for you: As far as the API goes, I'm inclined to make a CM with the above behavour available as a new class method on NamedTemporaryFile: Although, for the stdlib version, I wouldn't suppress the OS Error (I'd follow what we currently do for TemporaryDirectory). I disagree that it's unacceptable for close() and __del__() to behave differently. I don't think so. The web framework for perfectionists with deadlines. which case delete on CM exit. I agree. Example: Python3. You can simply store the tmpfile object, not its name, and then call seek (0) to go to the beginning to be ready to read. If __enter__() is called, close() closes the file but doesn't delete anything, and __exit__() closes the file (if open) and deletes it (even if it wasn't open). But also add an implementation of TemporaryFile() in Windows that uses O_TEMPORARY. wasn't open). Python's open() doesn't, not without an opener. Having to explicitly delete the file is exactly the kind of boilerplate one wants to avoid in situations like this. Do we need to have a separate issue raised for this problem? Daniel, Nick, shouldn't the context manager yield f within a with block? Your proposal, on the other, is a lot of work. I don't think implementing TemporaryFile() in Windows is separate from this issue. Another process that wants to delete dir won't be able to move the file out of the way. Eryk, thank you for clarifying. If "rescuing" (i.e. Eryk, forgive my ignorance, but aren't in your msg390814 you are proposing yet another enhancement (separate from the bpo-14243, discussed here), in this case for TemporaryFile in Windows systems? #PYTHON #: #How #to #use #tempfile.NamedTemporaryFile()? needed on windows systems to access file This is due to a security feature. correctly. dabrahams/zeroinstall@d76de03#L3R44 An example of data being processed may be a unique identifier stored in a cookie. On POSIX (only), a process that is terminated abruptly with SIGKILL cannot automatically delete any NamedTemporaryFiles it created. Feel like I suck at programming but I love it. Tip: You can also select more than one file to be deleted at the same time. My preferred solution would be to replace the binary delete argument of the current NamedTemporaryFile implementation with finer-grained options: If there any issues, contact us on - htfyc dot hows dot tech #PYTHON:HowtousetempfileNamedTemporaryFile()? if NamedTemporaryFile is used as a context manager, the file is closed *on context manager exit* and *not* when the file is closed. I'm OK with being voted down on that, though. It states that accessing it a second time while it is still open. comments sorted by Best Top New Controversial Q&A Add a Comment . The complicated dance in NamedTemporaryFile is only to make *del* work a bit more reliably during process shutdown (due to some messy internal problems with what CPython is doing at that point). I feel like that wouldn't work because if *we* can open a write handle, so could an attacker - but as I say, I'm not an expert). The NamedTemporaryFile() function creates a file in the same way as TemporaryFile() but with a visible name in the file system. I was providing a summary of a common use case that conflicts with using O_TEMPORARY to make it clear that this flag has to be omitted if we're not implementing something like a delete_on_close boolean option. Have a question about this project? In my PR I used solution, proposed by Eryk. The first line is closing the temporary file, and the second is getting it's filename. Trademarks are property of respective owners and stackexchange. I might be tempted to create a backports package for users of earlier Python versions to get the future behavior sooner. If you can in fact "change the way the file is opened on Windows so that it can be opened again without closing it first," that would be fine with me. By accepting all cookies, you agree to our use of cookies to deliver and maintain our services and site, improve the quality of Reddit, personalize Reddit content and advertising, and measure the effectiveness of advertising. delete=AFTER_CM_EXIT # delete after context manager exits Any other decision to be taken which I missed? Eryk, I agree, that implementing TemporaryFile() in Windows goes hand in hand with the decision to stop using O_TEMPORARY in NamedTemporaryFile(). I did search before I opened that issue, but search is currently somewhat broken and I did not find this issue. However, you're right that the exclusive read lock in the current implementation makes the default behaviour of NamedTemporaryFile significantly less useful on Windows than it is on POSIX systems, so the implementation should be changed to behave more like the POSIX variant. If the only issue with my PR is that default solution is not portable, then this can be simply changed within current PR by setting default of delete_on_close to fe equal to False. These are the top rated real world Python examples of tempfile.NamedTemporaryFile.write extracted from open source projects. init ( kwargs) code. But I haven't thought about how to handle the delete argument. I also want O_SHORT_LIVED. I know it is somewhat implicit in the fact that it is a context manager call, but that is not the only context the method name will be seen in. In addition, we create a *new* context manager, that simply creates the file at the start and deletes it at close of scope. Is there an actual known use case for the behaviour of deleting the file on close *rather* than at the end of the CM's scope? close() closes the file but doesn't delete anything, and On a side note, delete=True is the default: http://docs.python.org/library/tempfile#tempfile.NamedTemporaryFile Just don't specify it and you'll be fine. More posts you may like. To be explicit, I'm +1 on breaking backward compatibility in the minor form described by Ethan: if NamedTemporaryFile is used as a context manager, the file is closed *on context manager exit* and *not* when the file is closed. My version does not delete the file until the context manager exits, and *if* the context manager exits due to an exception it leaves the file in place and reports its location, to aid me in debugging. I'm OK with being voted down on that, though. A solution would be to define NamedTemporaryFile as follows: [code] class NamedTemporaryFile (TemporaryFile): def init (self, kwargs): kwargs.pop ('delete', True) # TODO: handle this delete flag. "delete_after" what? And this library is not designed for it, so users can't rely on the native functionality. (Especially since doing so would also breach backward compatibility guarantees). __exit__() closes the file (if open) and deletes it (even if it But I think Eryk's proposal is the most reasonable. So, no, we're not going to back away from the explicit guarantee in the NamedTemporaryFile docs: "If delete is true (the default), the file is deleted as soon as it is closed." Do I need to close or delete created NamedTemporaryFile here? CS degree is taking all my free time and I cant learn How do you deal with how frustrating it is to learn Press J to jump to the feed. In a release after the deprecation has been released, change the default to delete_when="exit" and drop support for None. Any thoughts on this? (Ignore previous comment; should have gone to #15659.). What problem are you trying to solve by this "unlinking trick"? on Windows so that it can be opened again without closing it first, What we really need for this use-case is a way to say, "delete on __del__ but not on close().". '.mp4'). everything subsequent occurs in the __exit__() method. trademark of the Django Software Foundation. :). Indeed, the current behaviour under Windows seems to be kind of a There seems to be still disagreements and I don't really know how to move this forward as I am not sure I understand the decision making mechanism in the Python community (especially when it comes to breaking backwards compatibility). mechanism to know whether it was called as a TemporaryFile. If there is no __enter__(), close() also deletes the file. IMO, what's more important is whether NamedTemporaryFile is *useful* to people, and what they want to use it *for*. (will it not stop working after some Windows patch)? I'm not suggesting breaking backward compatibility, either. I replied twice that I thought using the CM exit instead of O_TEMPORARY is okay for NamedTemporaryFile() -- but only if a separate implementation of TemporaryFile() that uses O_TEMPORARY is added at the same time. However, the fix is simple, the only backwards-compatible issue is the file would still be there /while a context manager was in use/ after it had been closed (which conforms to most, if not all, users of context managers) and a file would be left on disk in the event of a hard crash (hopefully a rare occurrence). If you would like to change your settings or withdraw consent at any time, the link to do so is in our privacy policy accessible from our home page. First, we have to import tempfile then the file is created using the TemporaryFile () function. It isn't clear to me that Windows supports that option, but I'm not an expert. manager work as expected with delete=True (ie: doesn't delete until I am trying to replace the insecure tempfile.mktemp() here (old code): pq_file = file_utils.extract_file_from_zip_onto_disk(zip_obj, pq_path, tempfile.mktemp()). I'm not marking it as a dup because my proposal is really a new feature. Sign up for a free GitHub account to open an issue and contact its maintainers and the community. Is the automatic deletion truly that valuable? NamedTemporaryFile() This function is similar to TemporaryFile() function. Daniel. Reddit and its partners use cookies and similar technologies to provide you with a better experience. bpo-14243: Optionally delete NamedTemporaryFile on content manager exit but not on file close, gh-58451: Add optional delete_on_close parameter to NamedTemporaryFile, https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilew#caching_behavior, : Add optional delete_on_close parameter to NamedTemporaryFile (, : Add optional delete_on_close parameter to NamedTempor. I looked at the code in the django.core.files.temp module, and see it makes a distinction between Windows and other systems: [code] Steve also wants Eryk Sun added the comment: At the moment, the TemporaryFile directly reuses NamedTemporaryFile for none-posix or cygwin systems.
Percentile Of Uniform Distribution, How To Convert Optional, How To Coach Someone Through A Panic Attack, Hisardale Pronunciation, Mongoose Validatesync,