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Safe inserts?


clay1

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This seems like something that should be easy to find, but I've been searching for a week for an answer.

 

I've got a site that has a public form that is filled out by unknown people.

 

I want to make sure my database and information is as safe as possible from attacks.

 

So I've got my form data in the post array. I need to check it to make it sure it is valid.

 

I've got most of that down.

 

But then what?

 

How do I get the information into my database in an efficient but secure way?

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You can use pg_escape_string on the date, then enclose it with single quotes.  Something like this:

 

$sql = "INSERT INTO tab (col1) VALUES (E'" . pg_escape_string($data) . "')";

 

The "E" says that there's an escaped string following.  You can leave it out and it'll generally work, but newer versions of postgres will generate a warning.

 

For data that should be a specific data type (such as an integer), you can filter the string so it only contains digits, for example.

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[code=php:0]$sql = "INSERT INTO tab (col1) VALUES (E'" . pg_escape_string($data) . "')";

 

 

Thanks.

 

So would I repeat this line for each column? I've got about 30 columns.

 

Or could I do a loop on something like:

 

[code=php:0]$sql = "INSERT INTO tab ($key) VALUES (E'" . pg_escape_string($data) . "')";

 

 

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Columns get added all with one statement.  For example:

 

$sql = "INSERT INTO tab (col1, col2, col3) VALUES (E'" . pg_escape_string($col1_data) . "', E'" . pg_escape_string($col2_data) . "', E'" . pg_escape_string($col3_data) . "')";

 

If you need to add multiple rows, then you should use a loop for that.  Just not for the columns (at least not normally)

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pg_insert()?  I didn't know that existed :)

 

Judging by the comment in the example in the php docs, it's injection safe.  But the function is also labelled as experimental :)

 

Anyway if it IS telling the truth and it is safe, then you definitely must NOT call pg_escape_string() yourself, as otherwise you'll get your strings escaped twice.  That's a real hassle when that happens.

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Yeah I removed the pg_escape_string after I checked my data

 

I've been testing pg_insert and pg_update and both have been working so far.

 

Still need to build in my verification and some other security stuff but basically taking running the two on $_POST works(key names need to match column names)

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