I have a php page that has blobs from my database  i need 404 image to display when there is no blob     &lt;?php $host = "localhost"; $username = "root"; $password = "12345678"; $db = "sis"; $PicNum = $_GET["PicNum"];  mysql_connect($host,$username,$password) or die("Impossível conectar ao banco.");  @mysql_select_db($db) or die("Impossível conectar ao banco.");  $result=mysql_query("SELECT * FROM usuarios WHERE id=$PicNum") or die("Impossível executar a query ");  $row=mysql_fetch_object($result);   Header("Content-type: image/gif");  echo $row-&gt;avatar;?&gt;
If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening?
When compiling a beamer presentation and using the following \author command  \author{Name \\ \texttt{my.email@domain.com}}   I get the following hyperref warning in my logfile  Package hyperref Warning: Token not allowed in a PDF string (PDFDocEncoding): (hyperref)                removing `\\' on input line 15.   Package hyperref Warning: Token not allowed in a PDF string (PDFDocEncoding): (hyperref)                removing `\new@ifnextchar' on input line 15.   I understand that this has to do with hyperref setting the PDF metadata, where the linebreak does’t make much sense and should be removed.  Trying to set  \hypersetup{pdfauthor={Name}}   does’t change the situation, seems like hyperref is still looking at the author command.  How do I get the desired display of author name with email and still keep hyperref happy? How to load a .NET assembly for reflection operations and subsequently unload it? How can I get debug log in Mavensmate Looking for Anime with a prince faking being mentally handicapped hiding a giant mech suit wreaking havoc This is all I can remember.  There are four worlds whose people and technology were all swapped so humans ended up with high tech mech suits that they used to kill each other. There was a supposedly handicapped prince who faked being mentally handicapped and had a giant mech suit hidden underground that he eventually used to wreak havoc on earth.  The protagonist also had a suit and he saved the day. He was in love with a girl who was from another world and when he saved the day, all the people and technology from the different worlds were sent back to their original one causing the girl to leave him. She had colored hair and the final scene was her waking up somewhere with some children commenting on her hair.  There may or may not have been a reference to the protagonists scars in the shape of the constellation of orion on his body.  Any ideas? I've searched the internet for two years trying to find it. I know how much space is required to install Ubuntu.  How much space does a Ubuntu installation take up on the disk? How to compute $\prod\limits^{\infty}_{n=2} \frac{n^3-1}{n^3+1}$ I am trying to sniff on a custom SPI-like bus protocol, which uses a unified bidirectional data line instead of separate MISO/MOSI. To make sense of the communication, I need to split it up into unidirectional lines before feeding them to my logic analyzer. Otherwise I wouldn't be able to see which device is responsible for which part of the signal. Since my devices won't talk to each other unless the protocol is carried out correctly, it's obvious that the bus splitting device has to be transparent to the actual agents communicating.  I tried to construct a bus splitting device, but failed as described . Since this question was maybe too specific and has not been answered, I want to ask more generally: Is there a bidirectional bus splitter that is able to split  into four wire SPI? Where could I buy such a device? (This seems similar to  question, only that I'm not talking about two really different protocols, so the answer does not apply). In principle only getting one direction would also suffice, since I could just subtract it from the full signal in order to retrieve the other half. And I'm also only interested in the master side of the communication.    The  seems to be a good candidate. Although it's advertised for use with I2C, it seems to be agnostic to the actual protocol on the lines. (As it does not even differentiate between DATA and CLOCK line for I2C.)     Splits I2C-bus signal into pairs of forward/reverse Tx/Rx, Ty/Ry signals for interface with opto-electrical isolators and similar devices that need unidirectional input and output signal paths.   As my devices operate on SPI mode 3 (polarity 1, idling on HIGH), the implementation of the receive pin should work:        sense the voltage state of the I2C-bus pin Sx (or Sy) and transmit this state to the pinTx (Ty respectively), and   sense the state of the pin Rx (Ry) and pull the I2C-bus pin LOW whenever Rx (Ry) is LOW.      But I am still puzzled on how this would actually work in sniffing this bidirectional bus. I could connect one device with the I2C line and grab its MOSI at Tx and MISO at Rx, but I would eventually have to connect both lines before feeding it to the other device, therefore making it impossible to separate the signals at my logic analyzer again. How can I connect the Tx/Rx for the slave while still being able to read them separately with a third device?  Edit: I now think this is actually not helping at all, since it leaves me with the same splitting issue as with out the device. I already have separate master and slave lines, I just don't know how to join them while still retrieving the separate directions.    I also stumbled upon the . It seems like this is a device designed for sniffing on buses, but I don't think it can help me in my case. Is there a mode where I can use it as a bridge on a bidirectional line and grab unidirectional signals off of it simultaneously?    Edit: I found this  which seems related to the issue. This does supposedly split the bidirectional line to feed it to two unidirectional isolators. The question is: Does this work for my setup? It describes the I2C lines being open-drain, whereas my lines are open-collector and also I'm not entirely sure if I could just leave out the isolator part and grab the signals from the lines or if these would have to be also hooked up to some transistor or be pulled high. I installed Oneiric as a guest OS in VirtualBox using the Mini CD. I installed the ubuntu-desktop package and everything seems to work fine - well, except for a font issue with the terminal:    As you can see, some of the letters overlap and it's difficult to read. I checked the settings and it the checkbox "Use the system fixed width font" is checked with "Monospace | 12" selected underneath it.    Edit: running the commands mentioned in the comments:  $ fc-match "Monospace" DejaVuSansMono.ttf: "DejaVu Sans Mono" "Book" $ gconftool --get /desktop/gnome/interface/monospace_font_name Monospace 10 $ debsums ttf-dejavu-core /usr/share/doc/ttf-dejavu-core/AUTHORS                                        OK /usr/share/doc/ttf-dejavu-core/BUGS                                           OK /usr/share/doc/ttf-dejavu-core/NEWS.gz                                        OK /usr/share/doc/ttf-dejavu-core/README                                         OK /usr/share/doc/ttf-dejavu-core/changelog.Debian.gz                            OK /usr/share/doc/ttf-dejavu-core/copyright                                      OK /usr/share/doc/ttf-dejavu-core/langcover.txt.gz                               OK /usr/share/doc/ttf-dejavu-core/status.txt.gz                                  OK /usr/share/doc/ttf-dejavu-core/unicover.txt.gz                                OK /usr/share/fonts/truetype/ttf-dejavu/DejaVuSans-Bold.ttf                      OK /usr/share/fonts/truetype/ttf-dejavu/DejaVuSans.ttf                           OK /usr/share/fonts/truetype/ttf-dejavu/DejaVuSansMono-Bold.ttf                  OK /usr/share/fonts/truetype/ttf-dejavu/DejaVuSansMono.ttf                       OK /usr/share/fonts/truetype/ttf-dejavu/DejaVuSerif-Bold.ttf                     OK /usr/share/fonts/truetype/ttf-dejavu/DejaVuSerif.ttf                          OK How to install Ubuntu 16.10 without any gui? I want to start my computer and it should open up to a CLI. I don't want a GUI, no fancy login screen etc.  I need a solution that does not use a minimal ISO because it requires an internet connection. I need an offline installation. Can compact sets completey determine a topology? Suppose that $\tau_1$ and $\tau_2$ are two topologies on a set $X$ with the property that $K\subset X$ is compact with respect to $\tau_1$ if and only if $K$ is compact with respect to $\tau_2$. Then is this enough information to determine whether $\tau_1 = \tau_2$?  If not (which is suspect to be the case) is there a nice counterexample, and what is the minimum amount of extra information required for $\tau_1 = \tau_2$?  I feel like there would be an issue regarding 'points at infinity.' Version Control: Entire site or just pieces? I've been using git to track changes in the plugins and themes I've developed for different sites. Each plugin or theme has their own repository in whichever local install of WordPress I happen to be using for that project. This works fine when I'm just working on one solitary plugin or theme.  But when I have a local version of an entire site which is a collection of different plugins, themes, WordPress core, etc. Should I be keeping that entire directory under version control?  Is there a best practice to always have a collection of repositories for each theme/plugin, or for each client site to have one monolithic repository that includes all the code used in the project (including the latest copy of WordPress via svn.) Could there be an eighth Horcrux? ARMA lag selection for ARMA-GARCH models How to show loading spinner in jQuery? In Prototype I can show a "loading..." image with this code:  var myAjax = new Ajax.Request( url, {method: 'get', parameters: pars,  onLoading: showLoad, onComplete: showResponse} );  function showLoad () {     ... }   In jQuery, I can load a server page into an element with this:  $('#message').load('index.php?pg=ajaxFlashcard');   but how do I attach a loading spinner to this command as I did in Prototype? I'm not sure if there's already an existing term for this, so I'm inventing my own. (tl;dr: I call them &quot;chameleon questions&quot; because they change every time you submit or edit an answer.  If you're already intimately familiar with the phenomenon, please skip past the first set of bullet points to where I ask for recommendations.)  I think many of us have experienced this on occasion:  You open up a narrow-looking question, usually dealing with some specific error message.  The question probably contains a snippet of sloppy but not quite awful code; code indicating that the author, typically a new/low-rep user, possibly a , doesn't really know what they're doing.  I'm not trying to be condescending here, they're probably very intelligent and hardworking, but in this specific case, they're clearly in way over their head.  However, as a question, it's not really too bad.  The goal and problem are both clearly stated.  The code is formatted (sort of).  Mort was polite and checked their spelling.  The question looks answerable, although from a rep perspective* it's an obvious dead-end, it's had maybe 3 views in the past 30 minutes.  So you decide, you know what, this person took the time to write up the question properly, they deserve an answer, put on your good citizen hat and throw them a bone.  You slog through the ugly code, find the offending line, direct their attention to it and explain why it's wrong and how it needs to be fixed.  Later, they leave a comment saying that yes, that was indeed the problem and your answer helped them fix it (great!).  Oh, but, now there's another problem (uh-oh...). Something else is broken.  After letting out a long sigh, you read the comment and/or edited question, roll up your sleeves, and write up Take 2, hoping that's the end of it.  And of course it's not the end.  Now maybe the error is gone, but it's not doing what it's supposed to.  If you're anything like me, your patience is now starting to wear thin. It's lousy code and you didn't volunteer to help them rewrite their whole app.  And of course, the question still only has 12 views, and nobody has upvoted either the question or your answer, including the person you're helping, so this is turning out to be a genuinely thankless task in all respects.  Welcome to &quot;Family Tech Support&quot;, Web 2.0 Edition.   * Which is of course just an arbitrary number that none of us care about. Not really, anyway. Not very much, at least.  So, here's where I get to my question.  At this point, do you:  Leave a comment, stating as politely as possible that you've done your best to help them answer the original question they asked, and if they have a new problem then they should start a new question?  (I did this once, and actually ended up with an accept, but I felt kind of guilty afterwards, I don't think anybody answered their 2nd question).  Bite the bullet and edit your answer a 3rd, 4th, 5th time, however many times it takes to resolve their issue, knowing full well that they may not even remember to accept the answer once you're done? (I may work for free on SO, but that doesn't mean my time is worthless.)  Just abandon the question, hoping that it will force Mort to start thinking for himself?  Something else?   I've tried all three of the above and none of them ever quite feel right. I do want to help, but at the same time there are a lot more &quot;lucrative&quot; questions I could be answering. And I don't mind spending a lot of time on an answer either, if the question is interesting or important to me, but debugging is dull work. I'd prefer not to reference specific questions here; I'm pretty sure that this is a shared experience, and my objective isn't to point fingers at &quot;misbehaving&quot; members.  I'm more looking for some practical advice on how to dig myself out of these pits of despair. Anybody have any other ideas? Often when I mistype a command such as ls (e.g. I hit ENTER before I type 's') there is a long (~2s) delay after the terminal displays:  bash: l: command not found...   I can understand the reasons for a similar delay after an incorrect password is entered, per . But why delay after an unrecognized command? Does FAIL_DELAY in /etc/login.defs affect this also? What effect does serial downvoting have on my rep cap? So I was the victim of serial downvoting the other day, and just had it automagically reversed. Rather than simply removing the previous votes, I was given a bonus lump of rep with the reason "serial downvote reversal". The downvotes and the bonus show up on different days. Since a whole day's quota worth of downvotes equates to quite a fraction of my daily rep cap, what happens in the following circumstances?   I get 200+ rep on a particular day, but I am serial downvoted (later reversed) back to under 200. Does this day count as reaching cap? I get 200+ rep the next day, and I am also credited back the rep. Is the rep bonus immune to the rep cap in the same way bounties are? On the day I get my rep bonus, it is enough to take me to 200 rep. Does this count as capping? Is there an elementary proof that $\sum \limits_{k=1}^n \frac1k$ is never an integer? How to calculate the correct focal length needed for a subject of a given size and distance? I need to purchase my first ever lens. So far I've only used lenses that were built into a camera. This specific lens is for the BlackMagic Deign Pocket Cinema Camera (a video only camera, but one that uses photography lenses). I would prefer this to be a prime lens.  I have tried to find the exact way to calculate the focal length of the lens I need but I have not been able to find a good resource to make this simple enough for my limited optics knowledge. Can you please explain a simple way to calculate the focal length of a lens given the following inputs as an example:    I would prefer a simplified mathematical explanation so that I may use it to make similar determinations in the future using a "" method.  I have . Using that method, I came up with:  Required lens focal length = 7.02mm sensor height x (77in / 36in) = 15mm   Is that correct? Replace background while using HDRI for lighting? How can I replace the background of my scene, but keep the reflections and lighting generated from my HDRI?