Anyone know to get a printer URI using CUPS API?
If not, does anyone know where I can find a list of allowable options that can be passed to cupsGetOption function.
Right now I can only find printer-info, printer-location, printer-make-and-model.
What your probably looking for is a the "device-uri". This is the uri to the remote device i.e lpd/socket/server address. If you're looking for the local uri it would be "printer-uri-supported" which would result in ipp://localhost:631/printers/printername. Here's how to get the remote uri...
#import <cups/cups.h>
const char * printer = "name_of_printer";
int num_dests;
cups_dest_t *dest,
*dests;
const char *value;
num_dests = cupsGetDests(&dests);
dest = cupsGetDest(printer, NULL, num_dests, dests);
if( dest == NULL){
return 0;
};
value = NULL;
if (dest->instance == NULL)
{
value = cupsGetOption("device-uri", dest->num_options, dest->options);
}
cupsFreeDests(num_dests, dests);
printf("uri - %s",value);
Related
I got one error with my blacklisted words, cannot read proprety ".id" of undefined. After "db.get(...)"
Thanks to help me!
// BLACKLISTED words
client.on('message', message => {
if(message.author.bot) return;
let wordarray = message.content.split(" ")
let filterWords = db.get(`blacklistwords_${message.guild.id}_${message.guild.id}`)
for(var i = 0; 1 < filterWords.length; i++) {
if(wordarray.includes(filterwords[i])) {
message.delete()
let Filter = new Discord.MessageEmbed()
.setColor('#FFE90F')
.setAuthor(message.guild.name, message.guild.iconURL())
.setDescription('<a:AttentionPink:706154679796760657> | **This word is blacklisted from this guild!** Do not say that again!')
.setTimestamp()
message.author.send(Filter)
break;
}
}
});
I think you should put your Guild ID in a var like so:
var guildID = message.guild.id;
If this is not working, well it's not the prettiest, but try using this line of code:
var guildID = bot.guilds.get(message.guild.id).id;
EDIT: Source
If the bot receives a message via DMs, it will not be able to get message.guild and that's why it says it is undefined. You can add something like if(message.channel.type === 'dm') return; so that the bot will not listen to DMs
I am currently using HttpDeclarePushto exploit the Server Push feature in HTTP/2.
I am able to successfully create all the parameters that this function accepts. But the issue is when HttpDeclarePushexecutes it returns a value of 1229 (ERROR_CONNECTION_INVALID) - https://learn.microsoft.com/en-us/windows/desktop/debug/system-error-codes--1000-1299-.
On further investigation I found that the HttpHeaderConnection in _HTTP_HEADER_ID (https://learn.microsoft.com/en-us/windows/desktop/api/http/ne-http-_http_header_id) is actually passed in the function as 'close'. That implies that on every request response the server closes the connection and that is also happening in my case, I checked it in the log.
Here is the code.
class http2_native_module : public CHttpModule
{
public:
REQUEST_NOTIFICATION_STATUS OnBeginRequest(IN IHttpContext * p_http_context, IN IHttpEventProvider * p_provider)
{
HTTP_REQUEST_ID request_id;
const HTTPAPI_VERSION version = HTTPAPI_VERSION_2;
auto pHttpRequest = p_http_context->GetRequest();
auto phttpRequestRaw = pHttpRequest->GetRawHttpRequest();
HANDLE p_req_queue_handle = nullptr;
auto isHttp2 = phttpRequestRaw->Flags;
try {
const auto request_queue_handle = HttpCreateRequestQueue(version, nullptr, nullptr, NULL, &p_req_queue_handle);
const auto verb = phttpRequestRaw->Verb;
const auto http_path = L"/polyfills.0d74a55d0dbab6b8c32c.js"; //ITEM that I want to PUSH to client
const auto query = nullptr;
request_id = phttpRequestRaw->RequestId;
auto headers = phttpRequestRaw->Headers;
auto connId = phttpRequestRaw->ConnectionId;
WriteEventViewerLog(L"OnBeginRequest - Entering HTTPDECLAREPUSH");
headers.KnownHeaders[1].pRawValue = NULL;
headers.KnownHeaders[1].RawValueLength = 0;
const auto is_success = HttpDeclarePush(p_req_queue_handle, request_id, verb, http_path, query, &headers);
sprintf_s(szBuffer, "%lu", is_success);
Log("is_success value", szBuffer); //ERROR CODE 1229 here
HttpCloseRequestQueue(p_req_queue_handle);
}
catch (std::bad_alloc & e)
{
auto something = e;
}
return RQ_NOTIFICATION_CONTINUE;
}
I even tried to update the header connection value as below but it still gives me 1229.
headers.KnownHeaders[1].pRawValue = NULL;
headers.KnownHeaders[1].RawValueLength = 0;
I understand from https://http2.github.io/http2-spec/ that HTTP/2 actually ignores the content in HTTP HEADERs and uses some other mechanism as part of its FRAME.
This brings us to the next question on how we can keep the connection OPEN and is it something related to the FRAME (similar to HEADER) that HTTP2 uses, if so, how C++ or rather Microsoft helps us to play and exploit with the FRAME in HTTP2?
How can I test whether a file that I'm opening in C# using FileStream is a "text type" file? I would like my program to open any file that is text based, for example, .txt, .html, etc.
But not open such things as .doc or .pdf or .exe, etc.
In general: there is no way to tell.
A text file stored in UTF-16 will likely look like binary if you open it with an 8-bit encoding. Equally someone could save a text file as a .doc (it is a document).
While you could open the file and look at some of the content all such heuristics will sometimes fail (eg. notepad tries to do this, by careful selection of a few characters notepad will guess wrong and display completely different content).
If you have a specific scenario, rather than being able to open and process anything, you should be able to do much better.
I guess you could just check through the first 1000 (arbitrary number) characters and see if there are unprintable characters, or if they are all ascii in a certain range. If the latter, assume that it is text?
Whatever you do is going to be a guess.
As others have pointed out there is no absolute way to be sure. However, to determine if a file is binary (which can be said to be easier than determining if it is text) some implementations check for consecutive NUL characters. Git apparently just checks the first 8000 chars for a NUL and if it finds one treats the file as binary. See here for more details.
Here is a similar C# solution I wrote that looks for a given number of required consecutive NUL. If IsBinary returns false then it is very likely your file is text based.
public bool IsBinary(string filePath, int requiredConsecutiveNul = 1)
{
const int charsToCheck = 8000;
const char nulChar = '\0';
int nulCount = 0;
using (var streamReader = new StreamReader(filePath))
{
for (var i = 0; i < charsToCheck; i++)
{
if (streamReader.EndOfStream)
return false;
if ((char) streamReader.Read() == nulChar)
{
nulCount++;
if (nulCount >= requiredConsecutiveNul)
return true;
}
else
{
nulCount = 0;
}
}
}
return false;
}
To get the real type of a file, you must check its header, which won't be changed even the extension is modified. You can get the header list here, and use something like this in your code:
using(var stream = new FileStream(fileName, FileMode.Open, FileAccess.Read))
{
using(var reader = new BinaryReader(stream))
{
// read the first X bytes of the file
// In this example I want to check if the file is a BMP
// whose header is 424D in hex(2 bytes 6677)
string code = reader.ReadByte().ToString() + reader.ReadByte().ToString();
if (code.Equals("6677"))
{
//it's a BMP file
}
}
}
I have a below solution which works for me.This is general solution which check all types of Binary file.
/// <summary>
/// This method checks whether selected file is Binary file or not.
/// </summary>
public bool CheckForBinary()
{
Stream objStream = new FileStream("your file path", FileMode.Open, FileAccess.Read);
bool bFlag = true;
// Iterate through stream & check ASCII value of each byte.
for (int nPosition = 0; nPosition < objStream.Length; nPosition++)
{
int a = objStream.ReadByte();
if (!(a >= 0 && a <= 127))
{
break; // Binary File
}
else if (objStream.Position == (objStream.Length))
{
bFlag = false; // Text File
}
}
objStream.Dispose();
return bFlag;
}
public bool IsTextFile(string FilePath)
using (StreamReader reader = new StreamReader(FilePath))
{
int Character;
while ((Character = reader.Read()) != -1)
{
if ((Character > 0 && Character < 8) || (Character > 13 && Character < 26))
{
return false;
}
}
}
return true;
}
I'm new to Stackoverflow and this will be my first question. My HTML5 player works fine on Internet Explorer but doesn't work on google chrome. I'm using a PlayReady stream which is encrypted with CENC. How can I let this work on chrome? I don't have access to the servers, they're run by third parties.
Thanks
Technically it is possible to support Widevine while you're stream is PlayReady. This is possible since you use CENC. Since you don't have access to the servers like you mentioned you can use a technique called PSSH Forging. It basically replaces the pieces to make chrome think it's Widevine, since it's CENC the CDM will decrypt the video and the stream will play.
For the sake of ease i'm going to assume you use DASH.
We have here a PSSH Box:
const widevinePSSH = '0000005c7073736800000000edef8ba979d64acea3c827dcd51d21ed0000003c080112101c773709e5ab359cbed9512bc27755fa1a087573702d63656e63221848486333436557724e5a792b32564572776e64562b673d3d2a003200';
You need to replace 1c773709e5ab359cbed9512bc27755fa with your KID.
And then at the part where you insert you'r segment in the SourceBuffer (before appendSegment) you can do the following:
let segment = args[0];
segment = new Uint8Array(segment);
const newPssh = widevinePSSH.replace('1c773709e5ab359cbed9512bc27755fa', psshKid);
const subArray = new Uint8Array(DRMUtils.stringToArrayBuffer('70737368'));
let index = 0;
const found = subArray.every((item) => {
const masterIndex = segment.indexOf(item, index);
if (~masterIndex) {
index = masterIndex;
return true;
}
});
if (found) {
return originalSourceBufferAppendBuffer.apply(this, [].slice.call(args));
}
segment = DRMUtils.uInt8ArrayToHex(segment);
// Inject the forged signal
// 70737368 = pssh
segment = segment.substr(0, segment.lastIndexOf('70737368') - 8) + newPssh + segment.substr(segment.lastIndexOf('70737368') - 8);
// Fix the MOOV atom length
// 6d6f6f76 = moov
const header = segment.substr(0, segment.indexOf('6d6f6f76') - 8);
const payload = segment.substr(segment.indexOf('6d6f6f76') - 8);
const newLength = Math.floor(payload.length / 2);
segment = header + DRMUtils.intToHex(newLength, 8) + payload.substr(8);
segment = decode(segment).b;
Sadly i can only share bits and pieces but this is roughly what you should do to get it working.
I am writing nginx module which construct nginx chain then write this chain buffer to nginx temporary file to use it later (just after write happen). I've been searching every page and the only solution come up is the one bellow:
// Create temp file to test
ngx_temp_file_t *tf;
tf = ngx_pcalloc(r->pool, sizeof (ngx_temp_file_t));
if (tf == NULL) {
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}
tf->file.fd = NGX_INVALID_FILE;
tf->file.log = nlog;
tf->path = clcf->client_body_temp_path;
tf->pool = r->pool;
tf->log_level = r->request_body_file_log_level;
tf->persistent = r->request_body_in_persistent_file;
tf->clean = r->request_body_in_clean_file;
// if (r->request_body_file_group_access) {
// tf->access = 0660;
// }
if (ngx_create_temp_file(&tf->file, tf->path, tf->pool, tf->persistent, tf->clean, tf->access) != NGX_OK) {
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}
if (ngx_write_chain_to_temp_file(tf, bucket->first) == NGX_ERROR) {
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}
This code does not return NGX_ERROR, is this meant nginx successful write temporary file into client_body_temporay_path? It the answer is yes, after that, I use fopen to open file, the file is not exist?
Can anyone please give me the right solution to handle ngx_write_chain_to_temp_file?
I find myself the solution
ngx_temp_file_t *tf;
tf = ngx_pcalloc(r->pool, sizeof (ngx_temp_file_t));
tf->file.fd = NGX_INVALID_FILE;
tf->file.log = nlog;
tf->path = clcf->client_body_temp_path;
tf->pool = r->pool;
tf->persistent = 1;
rc = ngx_create_temp_file(&tf->file, tf->path, tf->pool, tf->persistent, tf->clean, tf->access);
//ngx_write_chain_to_file(&tf->file, bucket->first, bucket->content_length, r->pool);
ngx_write_chain_to_temp_file(tf, bucket->first);
The only thing I cannot understand is if I set tf->persistentto false (0), after the file created, I cannot read from it even if I've not passed response to output_filter yet.