Using nodejs and iconv-lite to create a http response file in xml with charset windows-1252, the file -i command cannot identify it as windows-1252.
Server side:
r.header('Content-Disposition', 'attachment; filename=teste.xml');
r.header('Content-Type', 'text/xml; charset=iso8859-1');
r.write(ICONVLITE.encode(`<?xml version="1.0" encoding="windows-1252"?><x>€Àáção</x>`, "win1252")); //euro symbol and portuguese accentuated vogals
r.end();
The browser donwloads the file and then i check it in Ubuntu 20.04 LTS:
file -i teste.xml
/tmp/teste.xml: text/xml; charset=unknown-8bit
When i use gedit to open it, the accentuated vogal appear fine but the euro symbol it does not (all characters from 128 to 159 get messed up).
I checked in a windows 10 vm and in there all goes well. Both in Windows and Linux web browsers, it also shows all fine.
So, is it a problem in file command? How to check the right charsert of a file in Linux?
Thank you
EDIT
The result file can be get here
2nd EDIT
I found one error! The code line:
r.header('Content-Type', 'text/xml; charset=iso8859-1');
must be:
r.header('Content-Type', 'text/xml; charset=Windows-1252');
It's important to understand what a character encoding is and isn't.
A text file is actually just a stream of bits; or, since we've mostly agreed that there are 8 bits in a byte, a stream of bytes. A character encoding is a lookup table (and sometimes a more complicated algorithm) for deciding what characters to show to a human for that stream of bytes.
For instance, the character "€" encoded in Windows-1252 is the string of bits 10000000. That same string of bits will mean other things in other encodings - most encodings assign some meaning to all 256 possible bytes.
If a piece of software knows that the file is supposed to be read as Windows-1252, it can look up a mapping for that encoding and show you a "€". This is how browsers are displaying the right thing: you've told them in the Content-Type header to use the Windows-1252 lookup table.
Once you save the file to disk, that "Windows-1252" label form the Content-Type header isn't stored anywhere. So any program looking at that file can see that it contains the string of bits 10000000 but it doesn't know what mapping table to look that up in. Nothing you do in the HTTP headers is going to change that - none of those are going to affect how it's saved on disk.
In this particular case the "file" command could look at the "encoding" marker inside the XML document, and find the "windows-1252" there. My guess is that it simply doesn't have that functionality. So instead it uses its general logic for guessing an encoding: it's probably something ASCII-compatible, because it starts with the bytes that spell <?xml in ASCII; but it's not ASCII itself, because it has bytes outside the range 00000000 to 01111111; anything beyond that is hard to guess, so output "unknown-8bit".
I am trying to download Blob file from ORACLE DB. I used dbms_lob.substr to cut binary data on parts (max length of HEX field is 2,000). So I cut it, then I put data into .docx file. When I open it I see the message:
Word found a problem with content in file test777.docx
and asks me to repair the file. After the Office suite repairs, the document just opens fine. I am able to open the document.
The core problem I think in a screenshot:
[![enter image description here][1]][1]
After cutting remained quantity of a symbol of the last field is it is supplemented by '02'. So when I write it in a file and open it with binary view I see lots of spaces in there. As I understand that is a core problem.
[![enter image description here][2]][2]
Does anyone knows how to avoid it? I think the problem in method of downloading.
How to repair bunch of files like Office does? (I have nearly 100 files every month).
You didn't specify a variable name for the length of the blob so I will use BLOB_LENGTH. You need to make sure not to write out more than the full length. Also you do not want the MOD option on the FILE statement since you are creating the file not appending to an existing file.
data _null_;
length fv $ 120;
set blobs;
fv="k:\Folder\"||File_nm;
file writeout FILEVAR=fv recfm=n;
array blob[8] blob_1-blob_8;
do i=1 to 8 ;
len = max(0,min(2000,blob_length - 2000*(i-1)));
put blob[i] $varying2000. len;
end;
run;
I'm looking for a performance-oriented way to read a file into a buffer backwards (from end to beginning).
The zip file format has a crucial end of central directory record at the end of the file (it could be n bytes back, there is a signature I need to find to know I have got it, so I can't just read the last 22 bytes of the file since there is an optional 64K comment in there).
I couldn't find any discussion on Stack Overflow or using Google on how to accomplish this.
Check out this module: https://github.com/bnoordhuis/node-buffertools
You could use the reverse function given by the module, which creates a new buffer in memory of equal length and loops through the original buffer from the end, appending each element to the front of the new buffer.
You would be better off simply using a loop with the starting index as buffer.length - 1 and decrementing until you get the data you want.
My midlet is showing some images fine, but not others.
They are all 8-bit PNGs, but the ones that aren't displaying are the ones I have created myself in PhotoShop.
So I am thinking maybe my PhotoShop (CS6) settings are wrong...
PNG-8, Selective, Diffusion, Colors: 256, Dither: 100%, Matte: None, Web
Snap: 0%, Convert to sRGB: ticked, Width: 48, Height: 48, Percent: 100%,
Quality: Bicubic.
I've experimented with a few of these settings, but to no avail.
Any ideas?
There is a similar problem here but this is opposite to mine in that PhotoShop mends things in that case, rather than breaks things...
My code is...
image = Image.createImage("/img/loading1.png");
...and here is my stack trace:
java.io.EOFException
at javax.imageio.stream.ImageInputStreamImpl.readFully(
ImageInputStreamImpl.java:353)
at java.io.DataInputStream.readUTF(DataInputStream.java:609)
at javax.imageio.stream.ImageInputStreamImpl.readUTF(ImageInputStreamImpl.java:332)
at com.sun.kvem.png.PNGImageReader.parse_iTXt_chunk(PNGImageReader.java:447)
at com.sun.kvem.png.PNGImageReader.readMetadata(PNGImageReader.java:650)
at com.sun.kvem.png.PNGImageReader.readImage(PNGImageReader.java:1312)
at com.sun.kvem.png.PNGImageReader.read(PNGImageReader.java:1582)
at com.sun.kvem.midp.GraphicsBridge.loadImage(GraphicsBridge.java:2602)
at com.sun.kvem.midp.GraphicsBridge.createImageFromData(GraphicsBridge.java:2511)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at com.sun.kvem.sublime.MethodExecution.process(MethodExecution.java:42)
at com.sun.kvem.sublime.SublimeExecutor.processRequest(SublimeExecutor.java:63)
at javax.microedition.lcdui.Image.createImage(Image.java:315)
The image in question does exist - both in the project and in the jar that is built.
Here is the image in question:
According to the crash log, the PNG decoder in J2ME fails inside the non-critical chunk iTXt:1
> com.sun.kvem.png.PNGImageReader.readMetadata
> com.sun.kvem.png.PNGImageReader.parse_iTXt_chunk
> javax.imageio.stream.ImageInputStreamImpl.readUTF
> java.io.DataInputStream.readUTF
According to libpng documentation, the text part of an iTXt chunk must be valid UTF8:
... The remaining chunk data is the main UTF-8 text, either zlib-compressed or not, according to the compression flag. Since its length can be determined from the chunk length, it is not null-terminated. As with the other two text chunks, newlines should be represented by single line-feed characters (decimal 10), and all other control characters (1-9, 11-31, and 127-159) are discouraged.
and so normally this would indicate that the stream read is not valid UTF8 text - it contains 'raw' bytes higher than the plain ASCII range 0..127 that do not conform to UTF8 rules.
I found that not to be the case in the sample image. There is only one set of consecutive bytes that form a UTF8 code sequence, and it is a valid one:
<?xpacket begin="EFBBBF" id=" ..
(the bolded section represents 3 data bytes in hexadecimal notation). I first suspected this was the error:
If the BOM character appears in the middle of a data stream, Unicode says it should be interpreted as a "zero-width non-breaking space" (inhibits line-breaking between word-glyphs). In Unicode 3.2, this usage is deprecated in favour of the "Word Joiner" character, U+2060.[1] This allows U+FEFF to be only used as a BOM.
(http://en.wikipedia.org/wiki/Byte_order_mark)
.. and so a fully conforming UTF8 reader should inspect its bytes and throw an UTFDataFormatException when it encounters a BOM anywhere else than as the very first value. Surprisingly, this does not seem to be the problem! First of all, there is no indication any of the readUTF sources do anything else than only verify if the UTF8 code is valid on its own, irrespective of its value. There are lots of 'invalid' Unicode code points (values that do not represent a valid Unicode character or instruction), but it appears to me they are all silently ignored. But I noticed the common readUTF functions only implement a small subset of UTF8/Unicode (see, e.g., Modified UTF-8 in Oracle's documentation).
So the problem lies elsewhere. Another clue to this is that the error thrown is not UTFDataFormatException but rather EOFException, indicating the read buffer ran out of the number of bytes it was promised to contain.
(warning: pure conjecture follows)
Looking at a source of DataInputStream, I find this snippet of code:
588 public final static String readUTF(DataInput in) throws IOException {
589 int utflen = in.readUnsignedShort();
followed by a loop to read utflen bytes (not "Unicode characters"). This is wrong for an iTXt chunk, as it does not have a 'first word' to indicate its length. The number of bytes in the plain text can be derived from the chunk length (which is, per PNG convention, the total data length excluding the length long word, the iTXt signature itself, and the final CRC32 code) minus the length of the zero-terminated keyword name, language, and "translated keyword" strings, and the two bytes which indicate compression of the full plain text.
As a work-around, remove the iTXt chunks from your PNG images. The data itself -- XMP Metadata -- is most likely not interesting at all for your purposes (but feel free to read what benefits Adobe thinks it has). And if your workflow does not use it, it's just a useless hunk of uncompressed text, taking up 814 bytes of the total of 981 bytes in your sample image -- a whopping 83%!
You can use an external utility to remove extraneous data chunks; the command line for the popular pngcrush, for example, is
pngcrush -rem alla -rem text InputFile.png OutputFile.png
(from en.wikipedia.org/wiki/Pngcrush).
Or directly from Photoshop: if you save a PNG 'the usual way' with the "Save As" menu option, the metadata goes in and there is no checkbox to get rid of it. If you use "Save for Web & Devices" instead, you get a large dialog with a lot of handy options, such as a drop down list labelled "Metadata".
Choosing "All" I got an even larger file; my version of Photoshop creates a massive 3K chunk of XMP Metadata, including a 2K totally empty 'filler' block...
Selecting "Copyright" or "None" finally got rid of all the crud (presumably because I did not fill in any copyright information), and then you get a nice 169 bytes long PNG, in which the only metadata is that software used is called "Adobe ImageReady".
1 Which is kind of ironic. Per PNG specifications,
.. A decoder encountering an unknown chunk in which the ancillary bit is 1 can safely ignore the chunk and proceed to display the image.
(source)
This "ancillary bit" is the 5th bit of the first byte of the chunk ID: 0 (uppercase) = critical, 1 (lowercase) = ancillary, i.e., if the first character of the chunk ID is a capital, a PNG reader must read and interpret its data correctly, and if it's not, it can be skipped silently.
So technically, the writers of J2ME could safely have ignored this entire chunk. But they messed it up, attempt to read it, and now the code crashes on all programs that merely try to read the image data in PNGs which happen to contain iTXt chunks.
So here is what I've got:
The problem that I face requires me to take a specialized header from WAV1 , and put it as the header for WAV2, in order to make WAV2 work with the API that I'm using. However, whenever I try to replace the first 38 characters of WAV2 with the first 38 of WAV1, I get an error when I try to play the file, I get an error saying that it is not formatted properly. Both WAV1 and WAV2 play properly before the edit.
Do you guys have any idea on what I'm doing wrong?
Thanks so much for your help.
-Rhynorater.
Wav format is a standardised format (see https://ccrma.stanford.edu/courses/422/projects/WaveFormat/ for details about file format). I'm not sure what a "specialized" header is (perhaps you could clarify what your specialised header is?) as the format is standard - any variation would not be a wav file.
The first 38 bytes of a wav file are the header and should adhere to the standard. You cannot copy the header from one file and use it for another as the header contains information specific to the individual file (number of channels, sample rate, file length, etc).
If you both files playback normally (how are you testing this?) I'm not sure why the API you are using is not compatible (which API are you using?).