This REGEXP echos one thing, but enters into MySQL another. Why? - php

Question

I have a query that when I test it with "echo", works well:
$url = "http://search.twitter.com/search.json?q=&ands=&phrase=&ors=&nots=RT%2C+%40&tag=andyasks&lang=all&from=amcafee&to=&ref=&near=&within=15&units=mi&since=&until=&rpp=50";
$contents = file_get_contents($url);
$decode = json_decode($contents, true);
foreach($decode['results'] as $current) {
if(preg_match("/\?/", "$current[text]")){
echo $current[text]."<br />";
}
}
But when I change it to this to create a DB, it loses one record:
$url = "http://search.twitter.com/search.json?q=&ands=&phrase=&ors=&nots=RT%2C+%40&tag=andyasks&lang=all&from=amcafee&to=&ref=&near=&within=15&units=mi&since=&until=&rpp=50";
$contents = file_get_contents($url);
$decode = json_decode($contents, true);
foreach($decode['results'] as $current) {
$query = "INSERT IGNORE INTO andyasks (questions, date, user) VALUES ('$current[text]','$current[created_at]','Andy')";
if(preg_match("/\?/", "$current[text]")){
mysql_query($query);
}
}
Specifically, the Tweet it's skipping over is "amcafee: #andyasks What should Enterprise 2.0 conference attendees be sure to do while they're in Boston later this month? #e2conf". This echos from the first one, but is left out on the DB INSERT. Any thoughts?

Answer 1

There's a single quote in the string that it doesn't insert (my _emphasis_ added):
"amcafee: #andyasks What should Enterprise 2.0 conference attendees be sure to do while they**_'_**re in Boston later this month? #e2conf"
The bare single-quote is interpreted by MySQL as the end of the first value, and it turns the rest of the query into gibberish. You need to escape single quotes (i.e. turn "they're" into "they\'re" so that MySQL knows that the single quote is part of your string. Incidentally, single-quote tricks are the main source of SQL injection attacks, so you should always be wary of single-quotes.
If you're using the mysql extension, you should always use the mysql_real_escape_string function on any untrusted data:
$url = "http://search.twitter.com/search.jsonq=&ands=&phrase=&ors=&nots=RT%2C+%40&tag=andyasks&lang=all&from=amcafee&to=&ref=&near=&within=15&units=mi&since=&until=&rpp=50";
$contents = file_get_contents($url);
$decode = json_decode($contents, true);
foreach($decode['results'] as $current)
{
$query = "INSERT IGNORE INTO andyasks (questions, date, user) VALUES ('$current[text]','$current[created_at]','Andy')";
if(preg_match("/\?/", "$current[text]"))
{
mysql_real_escape_string($query);
mysql_query($query);
}
}

Answer 2

PHP/MySQL Debugging Tips
When you're echoing out debug statements, make sure you view the source of your HTML page to see what's actually being sent to mysql.
While viewing the source of your echo'd page, copy and paste the SQL query directly into the mysql console (or phpMyAdmin if you're using it) and see what happens.
Consider using a logging function instead of echoing out mysql statements. Here's a brain dead logger you can use
class BrainDeadLogger {
static public function log($output, $file='/tmp/test.txt') {
file_put_contents($file,"$output\n",FILE_APPEND);
}
}
BrainDeadLogger::log($sql);
And then monitor the log with something like
tail -f /tmp/test.txt
on the Unix command line. You can downloadTail for Windows, which should work similarly.