Update Delayed on Mysql and PHP

Wouldn’t it be nice if we could use UPDATE DELAYED in mysql just like we do use INSERT DELAYED? Unfortunately, the work around mysql created for this is to insert a record into the events table in order to separate UPDATE statement into another thread. There is a large overhead to inserting to then execute an update.

If you are using PHP with mysql, there is another work around.  PHP has a function called, register_shutdown_function, which will execute a function during the shutdown of processing a script file. So if we add an UPDATE LOW_PRIORITY sql statement wrapped in a function that is passed to register_shutdown_function, we can allow the user to receive the page without delay while the UPDATE statement waits until all locks on the table has been release before proceeding.

function update_delayed()
{
$sql = "UPDATE LOW_PRIORITY table_name SET col1 = 'something'";
mysql_query($sql, $conn);
}

register_shutdown_function('update_delayed');

I wonder if there are even better ways to handle this problem.

Getting Android emulator working with Google Maps API Key

I was trying to get an Android app that uses Google Maps API to display a MapView running on the emulator.  It took quite a bit of hair pulling to finally get it working.

First, I tried using a self-signed keystore instead of the the debug.keystore provided through the Android SDK.  I created my keystore using keytool -genkey from JDK.  Then I switch the app from using the default, debug.keystore, to my-new-self-signed.keystore.  Using keytool -list, I got the MD5 of the certificate that is needed to obtain a Google Map API key.  Then the API key was put into the MapView android:apikey attribute.  When I brought up the app in the emulator, I got a blank map grid screen.  The reason I wanted to use the self-signed keystore instead of the debug keystore is so I don’t have to obtain a new Map API key and change the code to reflect this upon releasing the app.

So, I decided to go with the debug.keystore and that worked fine.  Here is what I had to do.

  1. $ keytool -list -alias androiddebugkey -keystore <path_to_debug_keystore>.keystore -storepass android -keypass android
  2. Copy that MD5 and goto http://code.google.com/android/maps-api-signup.html
  3. Signup for an API key
  4. In my xml file that has the views for the activity, add
    <com.google.android.maps.MapView
     android:layout_width="fill_parent"
     android:layout_height="fill_parent"
     android:enabled="true"
     android:clickable="true"
     android:apiKey="example_Maps_ApiKey_String"
     />
  5. In the Manifest.xml file, add the permissions needed
    <uses-permission android:name=”android.permission.INTERNET”></uses-permission>
    <uses-permission android:name=”android.permission.ACCESS_FINE_LOCATION”></uses-permission>
  6. In the Manifest.xml file, add the maps library
    <uses-library android:name=”com.google.android.maps” />
    within the application tag
  7. The entire Manifest.xml looks like this
    <?xml version=”1.0″ encoding=”utf-8″?>
    <manifest xmlns:android=”http://schemas.android.com/apk/res/android”
    package=”com.informationideas.mapapp”
    android:versionCode=”1″
    android:versionName=”1.0.0″>
    <uses-permission android:name=”android.permission.INTERNET”></uses-permission>
    <uses-permission android:name=”android.permission.ACCESS_FINE_LOCATION”></uses-permission>
    <application android:icon=”@drawable/icon” android:label=”@string/app_name”>
    <uses-library android:name=”com.google.android.maps” />
    <activity android:name=”.ShowDesktop”
    android:label=”@string/app_name”>
    <intent-filter>
    <action android:name=”android.intent.action.MAIN” />
    <category android:name=”android.intent.category.LAUNCHER” />
    </intent-filter>
    </activity>
    </application>
    </manifest>
  8. The default activity file should look like this

    package com.informationideas.mapapp;
    import android.os.Bundle;
    import com.google.android.maps.MapActivity;

    public class ShowDesktop extends MapActivity {

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    }

    @Override
    protected boolean isRouteDisplayed() {
    // TODO Auto-generated method stub
    return false;
    }
    }

Now off to building cool things with the map!

PHP header redirect

Something to remember when using header location to redirect a page from a server-side script.  The output is redirected to the new page, but the logic on the original file will continue to execute.  Therefore, if there are database calls the changes to the data will still be made even though a header redirect was issued.

To solve the problem, make sure to issue an exit() command after a header location command.

Google Earth / Map Implementation Problem

One thing that was not documented fully at Google for integrating Google Earth into Google Map is that the function, getEarthInstance, is only available in the newest version of the Map API. I could not find exactly which version so the best way is to use v=2.x like in “http://maps.google.com/maps?file=api&v=2.x&key=yourkey” instead of specifying an exact version. Have fun with this new feature.

php strip_tags problem

I found that using php function, strip_tags, does not remove all the markup elements correctly from the subject content.  First of all, if an anchor link includes a line break, it will not be removed correctly.  Also, the style information is not properly removed as well.  In the following script, I also added in the regex to remove any content in between script tags, but that may or may not be necessary.

function strip_all_tags($content)
{
$content = preg_replace(‘/\n/’,’ ‘,$content);
$content = preg_replace(‘/<script.*<\/script>/U’,’ ‘,$content);
$content = preg_replace(‘/<style.*<\/style>/U’,’ ‘,$content);
$content = strip_tags(strtolower($content));
return $content;
}

The function will remove all line breaks so strip_tags will not have problems with finding all markups.  Since strip_tags does not remove <style> tags, the new function will remove them using regex.

asp:HyperLink With Dynamic URLs

Much headache to get this to work. The following format will allow dynamic url with multiple variables in the query string in a itemtemplate.

<asp:HyperLink ID=”HyperLink1″ runat=”server”
Text=”Link Text”
Target=”_blank”
NavigateUrl='<%# “~/mypage.aspx?var1=”+ Eval(“Var1”) + “&var2=” + Eval(“var2”)%>’>
</asp:HyperLink>

NOTE: Make sure any literal between <%# and %> uses double quotes NOT single quotes.

Other methods for handling dynamic NavigateUrl

Zencart and Ultimate URL – 1054 Unknown column ‘c.parent_id’ in ‘on clause’

Configuration:

Linux
Apache 1.3
Mysql 5
PHP 5
Zencart 1.3.5
Chemo Ultimate URL for Zencart 1.3.5

Problem:

After installation, the error message
1054 Unknown column ‘c.parent_id’ in ‘on clause’
shows up on any page in the catalog.

Fix:

Make the following change to /include/classes/seo.url.php
Original:

SELECT c.categories_id as id, c.parent_id, cd.categories_name as cName, cd2.categories_name as pName
FROM “.TABLE_CATEGORIES.” c,
“.TABLE_CATEGORIES_DESCRIPTION.” cd
LEFT JOIN “.TABLE_CATEGORIES_DESCRIPTION.” cd2
ON c.parent_id=cd2.categories_id AND cd2.language_id='”.(int)$this->languages_id.”‘
WHERE c.categories_id=cd.categories_id
AND cd.language_id='”.(int)$this->languages_id.”‘”;

Change:

“SELECT c.categories_id as id, c.parent_id, cd.categories_name as cName, cd2.categories_name as pName
FROM
“.TABLE_CATEGORIES_DESCRIPTION.” cd,
“.TABLE_CATEGORIES.” c
LEFT JOIN “.TABLE_CATEGORIES_DESCRIPTION.” cd2
ON c.parent_id=cd2.categories_id AND cd2.language_id='”.(int)$this->languages_id.”‘
WHERE c.categories_id=cd.categories_id
AND cd.language_id='”.(int)$this->languages_id.”‘”;

Zen Cart New Product Type Using Ultimate SEO URL Package

This post is to help those who are using Zen Cart and are using new product types with Ultimate SEO URL package installed. There are a couple of things to change in order to make everything work together as it took me a couple of hours to figure out. I hope this will help others save these couple of hours of hair pulling.

Prerequisite:

Zen Cart installed
New product type added
Ultimate SEO URL package installed
Goal:

Have the URLs for the products using the new product type show URLs in this format.

http://www.domain.com/[product name]-p-[product id].html

Changes Required:

NOTE: [handler_name] is the new product type name added.

  1. File – seo.url.php
    Original:
    $seo_pages = array(
    FILENAME_DEFAULT,
    FILENAME_PRODUCT_INFO,
    FILENAME_POPUP_IMAGE,
    FILENAME_PRODUCT_REVIEWS,
    FILENAME_PRODUCT_REVIEWS_INFO,
    );Result:

    $seo_pages = array(
    FILENAME_DEFAULT,
    FILENAME_PRODUCT_INFO,
    FILENAME_POPUP_IMAGE,
    FILENAME_PRODUCT_REVIEWS,
    FILENAME_PRODUCT_REVIEWS_INFO,
    FILENAME_[handler name]_INFO
    );
  2. File – seo.url.php
    Original:
    $this->reg_anchors = array(
    ‘products_id’ => ‘-p-‘,
    ‘cPath’ => ‘-c-‘,
    ‘manufacturers_id’ => ‘-m-‘,
    ‘pID’ => ‘-pi-‘,
    ‘products_id_review’ => ‘-pr-‘,
    ‘products_id_review_info’ => ‘-pri-‘,Result:
    $this->reg_anchors = array(
    ‘products_id’ => ‘-p-‘,
    ‘cPath’ => ‘-c-‘,
    ‘manufacturers_id’ => ‘-m-‘,
    ‘pID’ => ‘-pi-‘,
    ‘products_id_review’ => ‘-pr-‘,
    ‘products_id_review_info’ => ‘-pri-‘,
    ‘[handler name]_id’ => ‘-pji-‘,

  3. File – seo.url.php -> function parse_parameters
    Find “case ‘products_id’:”
    Within this case statement, add the following.case ($page == FILENAME_[handler name]_INFO):
    $url = $this->make_url($page, $this->get_product_name($p2[1]), ‘[
    handler_name]_id’, $p2[1], ‘.html’, $separator);
    break;
  4. File – [webroot]/includes/filenames.php
    Add the following definition.define(‘FILENAME_[handler name]_INFO’, ‘[handler name]_info’);
  5. File – [webroot]/.htaccess
    Add the following rewrite rule.RewriteRule ^(.*)-pji-(.*).html$ index\.php?main_page=[
    handler_name]_info&products_id=$2&%{QUERY_STRING} [L]