Bug report #13962
Text delimited file with carriage return line endings will not load in QGIS
Status: | Closed | ||
---|---|---|---|
Priority: | Normal | ||
Assignee: | - | ||
Category: | Data Provider/Delimited Text | ||
Affected QGIS version: | 2.12.0 | Regression?: | No |
Operating System: | Easy fix?: | No | |
Pull Request or Patch supplied: | No | Resolution: | end of life |
Crashes QGIS or corrupts data: | No | Copied to github as #: | 21976 |
Description
I am trying to load a .csv with carriage return line endings (the default for Microsoft Excel in Mac OSX). This has been broken for several iterations of QGIS and is not an issue when loading the file into other programs (e.g. R). Loading .csv files from Excel is one of the most common tasks in our lab and this is a large stumbling block when converting users to QGIS.
History
#1
Updated by Jürgen Fischer over 8 years ago
Note: via OGR it works (ie. "Add Vector Layer" / drag & drop into qgis window)
#2
Updated by Jürgen Fischer over 8 years ago
QGIS (Qt's TextStream) expects "\
\
" (CRLF; windows/dos style) or "\
" (LF; unixoid) as line ending. Nowadays "\
" is apparently normal on Mac - unfortunately Excel on Mac seems to differ (and still follows what was usual before OSX).
#3
Updated by Dewey Dunnington over 8 years ago
I agree it's odd behaviour and definitely Excel's fault, but it's difficult to run tutorials having to tell people they have to open files and save them using OpenOffice in order to get their field data into QGIS. If somebody tells me where to look I'm happy to try to fix!
#4
Updated by Sebastian Dietrich over 8 years ago
Since the corresponding Qt-Bug is set to won't fix you would have to work on the delimited text provider, probably by creating a subclass of QTextStream and using it at this point.
#5
Updated by Dewey Dunnington over 8 years ago
If it were a Python issue I'd happily fix it, but I know nothing about C++ so it would be a bad idea for me to try. QTextStream::readLine() calls QTextStream::readLineInto(), which looks like this (in Qt 5.5):
bool QTextStream::readLineInto(QString *line, qint64 maxlen) { Q_D(QTextStream); // keep in sync with CHECK_VALID_STREAM if (!d->string && !d->device) { qWarning("QTextStream: No device"); if (line && !line->isNull()) line->resize(0); return false; } const QChar *readPtr; int length; if (!d->scan(&readPtr, &length, int(maxlen), QTextStreamPrivate::EndOfLine)) { if (line && !line->isNull()) line->resize(0); return false; } if (Q_LIKELY(line)) line->setUnicode(readPtr, length); d->consumeLastToken(); return true; }
I don't know enough about C++ to figure out what d is or what the value of QTextStreamPrivate::EndOfLine might be, but it may be a start?
#6
Updated by Nathan Woodrow over 8 years ago
This is how EndOfLine is used in the Qt source
case EndOfLine:
778 if (ch == QLatin1Char('\
')) {
779 foundToken = true;
780 delimSize = (lastChar == QLatin1Char('\
')) ? 2 : 1;
781 consumeDelimiter = true;
782 }
783 lastChar = ch;
784 break;
#7
Updated by Nathan Woodrow over 8 years ago
The main issue here is that stream the file so we can't just do a normal replace like you would.
We could do something in the UI like "Corrently OSX Excel line endings" which would mean we need to read, update and write the file back, or read into memory.
Thoughts. It's annoying having to add work around but it is an annoying as hell bug given how it's OS X and Excel.
#8
Updated by Dewey Dunnington over 8 years ago
- File textmodule.py
added
The following works in PyQt4, but I did not heavily test. For tests I did see the uploaded file. Perhaps this could be converted to C++?
from PyQt4.QtCore import QTextStream, QString #subclass QTextSream class MacAwareQTextStream(QTextStream): def __init__(self, qstring): QTextStream.__init__(self, qstring) self.newline = None def readLineWithNewline(self, newline, bufferlen=128, prefix=QString("")): start = self.pos() buf = self.read(bufferlen) if buf.contains(newline): pos = buf.indexOf(newline) line = buf.left(pos) if not self.seek(start+pos+newline.length()): self.seek(line.length()) return line.prepend(prefix) elif buf.length() < bufferlen: #is last line return buf.prepend(prefix) else: #try bigger buffer return self.readLineWithNewline(newline, bufferlen*2, buf.prepend(prefix)) def findNewline(self, bufferlen): buf = self.read(bufferlen) if buf.contains("\ \ "): return QString("\ \ ") elif buf.contains("\ "): return QString("\ ") elif buf.contains("\ "): buf2 = self.read(1) if buf2 == "\ ": return QString("\ \ ") else: return QString("\ ") elif self.atEnd(): #no new line in file return QString("\ ") else: return self.findNewline(bufferlen*2) def readLine(self): bufferlen = 1024 if self.newline is None: #need to determine newline chars self.newline = self.findNewline(bufferlen) self.seek(0) return self.readLineWithNewline(self.newline, bufferlen)
#9
Updated by Matthias Meisser about 8 years ago
- Target version set to Version 2.14
I confirm this bug for 2.14 (Essen) and 2.2 (Valmiera).
Usually GIS users aren`t nessesarly IT experts, it would be nice, if QGIS avoids crashes by unexpected data :)
I see your point, that the bug couldn't fixed upstream at the component itself. On the other hand, it would be nice when there would be an embedded workaround.
My usecase was: http://koenigstuhl.geog.uni-heidelberg.de/~mover/rostock.zip
#10
Updated by Giovanni Manghi over 7 years ago
- Regression? set to No
- Easy fix? set to No
#11
Updated by Giovanni Manghi over 5 years ago
- Resolution set to end of life
- Status changed from Open to Closed
End of life notice: QGIS 2.18 LTR
Source:
http://blog.qgis.org/2019/03/09/end-of-life-notice-qgis-2-18-ltr/
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