The Error Message – Page 4

HTML

Problem: When submitting a form, seems like another form gets submitted

Post author By thalissar
Post date December 10, 2007

Actually, I had two forms on the same page, one with the GET method (let’s call it get_form), the other with the POST method (we’ll call it post_form). When I pressed the submit button of get_form it seemed that the post_form got submitted. In fact, all the variables in get_form and post_form were passed with the POST method.

So the natural thing that came into my mind was that the two forms were intersecting. But how? I knew for sure they were separate forms because get_form was in a file that I was including in the file that contained post_form, after post_form.

After verifying the HTML source over and over again I finally solved the mistery. There was a stupid mistake I made: I did not close post_form properly. Instead of using the form closing tag </form> at the end of post_form, i put the form opening tag <form> and every time I checked for the problem, I missed an important detail: the lack of the slash sign.

Conclusion: When opening a HTML element, make sure to close it accordingly.

How to receive a failure notice when the recipient cannot be reached after sending an email using the PHP mail() function

Post author By thalissar
Post date December 9, 2007

I could not receive a failure notice when sending email to an email address that does not exist ($to_address), using this code:

$subject = "Email subject";
$message = "line1\r\nline2\r\nline3";
$headers  = "MIME-Version: 1.0\r\n";
$headers .= "Content-type: text/plain; charset=iso-8859-1\r\n";
$headers .= "To: <$to_email>\r\n";
$headers .= "From: Me <$my_email_address>\r\n";
$headers .= "Return-Path: <$my_return_email_address>r\n";
mail($to_email, $subject, $message, $headers);

The problem was that the email address I wanted to receive the failure notices to ($my_return_email_address) was not the same as the value of the configuration option sendmail_from in the php.ini file (Apache web server installed on a machine with the Windows Professional operating system). So the failure notices were sent to the sendmail_from email address if this was an existing address, instead of the email address specified in the Return-path header of the email.

The solution is replacing the lines:

$headers .= "Return-Path: <$my_return_email_address>r\n";
mail($to_email, $subject, $message, $headers);

with:

// when the PHP server runs on Windows
ini_set(sendmail_from, $my_return_email_address);
mail($to_email, $subject, $message, $headers);
ini_restore(sendmail_from);

// when the PHP server runs on UNIX
mail($to_email, addslashes($subject), $message, $headers, "-r $my_return_email_address");

This means that, before sending the email, we set the value of the sendmail_from configuration option to $my_return_email_address and we restore the default value of the configuration option after the email is sent.

How to HTML JavaScript Tutorial

How to check/uncheck a bunch of checkboxes without using ids for the checkbox inputs

Post author By thalissar
Post date December 9, 2007

My solution of checking/unchecking a group of HTML checkboxes using Javascript implies using an array of checkboxes, which means naming all the inputs of type ‘checkbox’ like array_name[]. Example:

<form name="cb_form">
<input type="checkbox" name="cb[]" value="0" />Zero
<input type="checkbox" name="cb[]" value="1" />One
<input type="checkbox" name="cb[]" value="2" />Two
<input type="checkbox" name="cb[]" value="3" />Three
</form>

In this example, the name of the checkboxes array is cb.

Next, we place two links for checking/unchecking all checkboxes in our array. If someone clicks one of these links, the checkAll() JavaScript function is called:

<a href="" onclick="checkAll('cb_form', 'cb[]', true); return false;">Check all<a>
<a href="" onclick="checkAll('cb_form', 'cb[]', false); return false;">Uncheck all<a>

The checking/unchecking all checkboxes function in JavaScipt looks like this:

function checkAll(form_name, cb_name, value)
{
var cb_arr = document.forms[form_name].elements[cb_name];
// if the checkboxes exist
if(cb_arr)
{
// if the number of checkboxes is at least 2
if(cb_arr.length > 1)
{
// for each checkbox
for(i = 0; i < cb_arr.length; i++)
{
// check (value == true) or uncheck (value == false) it
cb_arr[i].checked = value;
}
}
else // cb_arr.length is undefined which means there is a single checkbox element that is not considered an array of one element
{
cb_arr.checked = value;
}
}
}

Note that if we only have one checkbox, the variable cb it is not considered an array, but a normal variable. This is useful in the situation of dinamically generated HTML pages (using PHP, for example) and the number of checkboxes varies from page to page.

You can test the example here:

Check all Uncheck all

PHP

Warning: mail(): SMTP server response: 451 See http://pobox.com/~djb/docs/smtplf.html. in path_to_php_file on line #

Post author By thalissar
Post date December 8, 2007
89 Comments on Warning: mail(): SMTP server response: 451 See http://pobox.com/~djb/docs/smtplf.html. in path_to_php_file on line #

Full error message: Warning: mail(): SMTP server response: 451 See http://pobox.com/~djb/docs/smtplf.html. in path_to_php_file on line #

This is an error message that I got lots of times and it was always the same problem. So I decided to write here the solution for the next time I encounter it and I thought it might also help other people.

So I tried to send an email in plain text using the PHP function mail() :

// consider this being an existing email address
$to_address = "abc@def.com";
$subject = "Email subject";
$message = "line1
line2
line3";
$headers  = "MIME-Version: 1.0\r\n";
$headers .= "Content-type: text/plain; charset=iso-8859-1\r\n";
$headers .= "To: <".$to_email.">\r\n";
$headers .= "From: Me <".$my_email_address.">\r\n";
mail($to_email, $subject, $message, $headers);

It worked fine with Apache server running on Linux operating system, but I got the error message mentioned before with the server running on Windows.
It looks like while Unix-based systems recognize \n character (the equivalent in PHP of LF – line feed) as a newline even when sending emails, Windows systems are stricter in comunicating using some textual Internet Protocols (such as SMTP) that mandate the line terminator to be the ASCII CR+LF (carriage return + line feed) sequence, which is abstracted in PHP to \r\n character sequence.

So the problem was the $message variable. The correct way to assign the multiple lines value to it is:

$message = "line1\r\nline2\r\nline3";  // separate the lines with \r\n
// or,  elegantly:
$message = "line1\r\n";
$message .= "line2\r\n";
$message .= "line3";

And now it works on Windows, too.

C++ Visual Studio

warning C4244: ‘argument’ : conversion from ‘double’ to ‘int’, possible loss of data

Post author By gbl
Post date August 12, 2007
1 Comment on warning C4244: ‘argument’ : conversion from ‘double’ to ‘int’, possible loss of data

Full error message: warning C4244: ‘argument’ : conversion from ‘double’ to ‘int’, possible loss of data

Error occured on Visual Studio 2003 when compiling a C++ project.

The warning occurred because i was calling the abs function and i did not have included yet the math.h file. The reason that this warning appeared was due to the abs function that was already loaded with other libraries (stdlib.h) and it had only one defined as int abs(int) but I needed the double abs(double) overload. This way the compiler needed to let me know about the implicit cast from double to int.

Example:

double y = 1.2454;
double x = abs((double)y);

Fix:

#include <math.h>

The fix in my case is the following code added to the header of the file #include <math.h>

Hibernate Java MySQL

org.hibernate.HibernateException: identifier of an instance of members.Appointment was altered from 8 to 8

Post author By thalissar
Post date August 6, 2007
6 Comments on org.hibernate.HibernateException: identifier of an instance of members.Appointment was altered from 8 to 8

Full error message:

Exception occurred during event dispatching:
org.hibernate.HibernateException: identifier of an instance of members.Appointment was altered from 8 to 8
at org.hibernate.event.def.DefaultFlushEntityEventListener.checkId(DefaultFlushEntityEventListener.java:58)
at org.hibernate.event.def.DefaultFlushEntityEventListener.getValues(DefaultFlushEntityEventListener.java:157)
at org.hibernate.event.def.DefaultFlushEntityEventListener.onFlushEntity(DefaultFlushEntityEventListener.java:113)
at org.hibernate.event.def.AbstractFlushingEventListener.flushEntities(AbstractFlushingEventListener.java:196)
at org.hibernate.event.def.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:76)
at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:26)
at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1000)
at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:338)
at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:106)
at members.AppointmentDialog.jButtonSaveActionPerformed(AppointmentDialog.java:279)
at members.AppointmentDialog.access$000(AppointmentDialog.java:21)
at members.AppointmentDialog$1.actionPerformed(AppointmentDialog.java:101)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1849)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2169)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:420)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
at java.awt.Component.processMouseEvent(Component.java:5517)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3135)
at java.awt.Component.processEvent(Component.java:5282)
at java.awt.Container.processEvent(Container.java:1966)
at java.awt.Component.dispatchEventImpl(Component.java:3984)
at java.awt.Container.dispatchEventImpl(Container.java:2024)
at java.awt.Component.dispatchEvent(Component.java:3819)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4212)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3892)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3822)
at java.awt.Container.dispatchEventImpl(Container.java:2010)
at java.awt.Window.dispatchEventImpl(Window.java:1791)
at java.awt.Component.dispatchEvent(Component.java:3819)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:463)
at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:242)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:163)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:153)
at java.awt.Dialog$1.run(Dialog.java:535)
at java.awt.Dialog$2.run(Dialog.java:563)
at java.security.AccessController.doPrivileged(Native Method)
at java.awt.Dialog.show(Dialog.java:561)
at java.awt.Component.show(Component.java:1302)
at java.awt.Component.setVisible(Component.java:1255)
at admin.AdminOptionsForm.jButtonSetAppointmentActionPerformed(AdminOptionsForm.java:238)
at admin.AdminOptionsForm.access$800(AdminOptionsForm.java:24)
at admin.AdminOptionsForm$9.actionPerformed(AdminOptionsForm.java:145)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1849)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2169)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:420)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
at java.awt.Component.processMouseEvent(Component.java:5517)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3135)
at java.awt.Component.processEvent(Component.java:5282)
at java.awt.Container.processEvent(Container.java:1966)
at java.awt.Component.dispatchEventImpl(Component.java:3984)
at java.awt.Container.dispatchEventImpl(Container.java:2024)
at java.awt.Component.dispatchEvent(Component.java:3819)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4212)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3892)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3822)
at java.awt.Container.dispatchEventImpl(Container.java:2010)
at java.awt.Window.dispatchEventImpl(Window.java:1791)
at java.awt.Component.dispatchEvent(Component.java:3819)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:463)
at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:242)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:163)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:157)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:149)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:110)

In Java, I had a class Appointment mapped to a MySQL table `appointment` using Hibernate as follows:

<hibernate-mapping>
<class name="members.Appointment" table="appointment">
<id name="idAppointment" column="idappointment" type="short">
<generator class="native"/>
</id>
<many-to-one name="member" column="idmember" not-null="true" foreign-key="fk_idmember"/>
<property name="startDate" type="timestamp" column="start_date"/>
<property name="duration" type="short" column="duration" length="3"/>
<property name="cancelled" type="boolean"/>
</class>
</hibernate-mapping>

I was getting the error when inserting a new appointment into the database.

The problem was that the idAppointment member variable in the Java class and the idappointment field in the MySQL database table were of the type int. So why the hell did I have the type short in the mapping? The answer is simple: because of the copy paste. So the correct code is:

<id name="idAppointment" column="idappointment">
<generator class="native"/>
</id>

Conclusion: copy paste is sometimes evil.

C++ Visual Studio

error C2724: ‘ClassName::FunctionName’ : ‘static’ should not be used on member functions defined at file scope

Post author By gbl
Post date July 30, 2007
2 Comments on error C2724: ‘ClassName::FunctionName’ : ‘static’ should not be used on member functions defined at file scope

Full error message: error C2724: ‘ClassName::FunctionName’ : ‘static’ should not be used on member functions defined at file scope

Error occurred in Visual Studio 2003 while declaring a static function.

Header file:

class MyClass {
public:
static void FunctionName();
};

Source file:

static void MyClass::FunctionName() {
return 0;
}

The error occurs because i used the ‘static’ modifier in the source file as well as the header file.

The fix is: Remove the ‘static’ modifier from the source file

So the code in the source file will become:

void MyClass::FunctionName() {
return 0;
}

Hibernate Java MySQL

java.sql.SQLException: Cannot convert value ‘0000-00-00 00:00:00’ from column 9 to TIMESTAMP

Post author By thalissar
Post date July 26, 2007
3 Comments on java.sql.SQLException: Cannot convert value ‘0000-00-00 00:00:00’ from column 9 to TIMESTAMP

Full error message:

Exception in thread "main" org.hibernate.exception.GenericJDBCException: could not execute query
at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:103)
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:91)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
at org.hibernate.loader.Loader.doList(Loader.java:2223)
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2104)
at org.hibernate.loader.Loader.list(Loader.java:2099)
at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:378)
at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:338)
at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:172)
at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1121)
at org.hibernate.impl.QueryImpl.list(QueryImpl.java:79)
at admin.MembersTableModel.<init>(MembersTableModel.java:43)
at admin.AdminOptionsForm.initComponents(AdminOptionsForm.java:98)
at admin.AdminOptionsForm.<init>(AdminOptionsForm.java:32)
at managemembers.Main.main(Main.java:45)
Caused by: java.sql.SQLException: Cannot convert value '0000-00-00 00:00:00' from column 9 to TIMESTAMP.
at com.mysql.jdbc.ResultSet.getTimestampFromBytes(ResultSet.java:6864)
at com.mysql.jdbc.ResultSet.getTimestampInternal(ResultSet.java:6899)
at com.mysql.jdbc.ResultSet.getTimestamp(ResultSet.java:6218)
at com.mysql.jdbc.ResultSet.getTimestamp(ResultSet.java:6256)
at com.mchange.v2.c3p0.impl.NewProxyResultSet.getTimestamp(NewProxyResultSet.java:3394)
at org.hibernate.type.TimestampType.get(TimestampType.java:30)
at org.hibernate.type.NullableType.nullSafeGet(NullableType.java:163)
at org.hibernate.type.NullableType.nullSafeGet(NullableType.java:154)
at org.hibernate.type.AbstractType.hydrate(AbstractType.java:81)
at org.hibernate.persister.entity.AbstractEntityPersister.hydrate(AbstractEntityPersister.java:2096)
at org.hibernate.loader.Loader.loadFromResultSet(Loader.java:1380)
at org.hibernate.loader.Loader.instanceNotYetLoaded(Loader.java:1308)
at org.hibernate.loader.Loader.getRow(Loader.java:1206)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:580)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.doList(Loader.java:2220)
... 11 more

My example:

// the Java class

public class Member  {
// some private member attributes
private Date addedDate;
// proper getter and setter methods
}

<!– the Hibernate mapping–>

<hibernate-mapping>
<class name="managemembers.Member" table="member">
<!-- some mappings here-->
<property name="addedDate" type="timestamp" column="added_date"/>
</class>
</hibernate-mapping>

# The MySQL table

CREATE TABLE `member` (
# some fields here
`added_date` DATETIME,
) ;

So I was mapping a java.util.Date field in the POJO to a MySQL DATETIME field.

The error occured while I was trying to retrieve the data from the member database table.

The problem was that I had DATETIME values in the database with all-zero components (0000-00-00 …), so the solution was to set all the added_date field values with all-zero components to NULL and to be careful to set a valid DATETIME value or NULL into the added_date field each time I inserted a new row.

Conclusion: You have 2 choices: either set the date field in the table to a NULL value either set it to a valid date.

C++ Visual Studio

error LNK2001: unresolved external symbol private: static …

Post author By gbl
Post date July 19, 2007
20 Comments on error LNK2001: unresolved external symbol private: static …

Full error message: error LNK2001: unresolved external symbol “private: static <type> * <Class>::<memberVariable>” (?<memberVariable>@<C@@0PADA)

Error occured on Visual Studio 2003 when compiling a C++ project.

The error occurred because memberVariable was a static variable and it wasn’t initialized.

Example:

class A {
static char * filename;
static void F(void);
} ;

Fix:

char * A::filename = NULL;

The fix in my case is the following code added to the implementation of the <Class>:
<type> <Class>::<memberVariable> = <initValue>;

Apache Web Server XML XSLT

An XSLT stylesheet does not have an XML mimetype:

Post author By gbl
Post date June 8, 2007
4 Comments on An XSLT stylesheet does not have an XML mimetype:

Full error message: Error loading stylesheet: An XSLT stylesheet does not have an XML mimetype:

Error occured on Firefox 2.0 when working with XML, XSLT.

xml file:

<?xml version="1.0" encoding="utf-8" ?>
<?xml-stylesheet type="text/xsl" href="product-list.xslt"?>
<f>PRODUCT DETAILS</f>

xslt file

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<stylesheet version="1.0" xmlns="http://www.w3.org/1999/XSL/Transform">
<template match="/">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>aaa</title>
</head>
<body leftmargin="0" topmargin="0" marginwidth="0" marginheight="0" onLoad="alert('x');">
<value-of select="f"/>
</body>
</html>
</template>
</stylesheet>

The error occurs because the web server (in my case Apache) had this entry in the mime.types file:

text/xml            xml xsl

The fix in my case is:
Change extenstion from xslt to xls on the stylesheet file or add xslt to the text/xml entry in mime.types file in Apache.