Assuming you’re running a Debian server (I have 6.0 Squeeze), on which WordPress is installed in /var/www/site/public_html:

1) Install required packages. I used vsftpd.

sudo apt-get install vsftpd openssl

2) Configure vsftpd. I set the following options in /etc/vsftpd.conf

# Enable only local users, no anonymous
anonymous_enable=NO
local_enable=YES
write_enable=YES
local_umask=022

# Allow only our special FTP user
userlist_enable=YES
userlist_deny=NO
userlist_file=/etc/vsftpd.allow_list

# Here's the security trick -- listen only on the local interface to 
# prevent external connections
listen_address=127.0.0.1

# Enable debugging until everything works :)
log_ftp_protocol=YES

3) Add a user for ftp access

# Add the user
sudo useradd ftpsecure -d /var/www

# Set a password. Since vsftpd is only listening on localhost, the 
# security of this password isn't too important.
sudo passwd ftpsecure

4) Turn on vsftpd:

sudo /etc/init.d/vsftpd restart

5) Set permissions for ftpsecure to access your wordpress files. I use access control lists (ACLs), but you could use chown/chmod if you want. These may seem like a bit to permissive — keep in mind that the only way ftpsecure can log in is from your server.

setfacl -m u:ftpsecure:r-x /var/www/site/

# The updater needs access to the root site
setfacl -R -m u:ftpsecure:rwx /var/www/site/public_html
setfacl -R -d -m u:ftpsecure:rwx /var/www/site/public_html

7) Tell WordPress about your FTP credentials. In /var/www/site/public-html/wp-config.php:

define('FTP_HOST', 'localhost');
define('FTP_USER', 'ftpsecure');
define('FTP_PASS', '<password>');

6) Run an update. If WordPress asks for the connection type, choose FTP. Try getting WordPress to update a plugin or the entire site. If it fails, view the log with

tail -f /var/log/vsftpd.log

and run the update again. You’ll be able to tell from the log if there was a permission problem.

7) Disable logging. Remove the line

log_ftp_protocol=YES

in /etc/vsftpd.conf

8) You’re done!

Comment below if these steps didn’t work for you.

For reference, I used:

• Updating WordPress via installed SSL FTP Server on Debian (FTPS)
• vsftpd Configuration Manual
• How To Configure WordPress To Remember FTP Details

const Matrix<4> m4 = Identity;
Vector<3> v3 = project(m4[3]);

With the library I was using, TooN 2.0.0 beta8, this resulted in a compile error. The error stated that when the vector returned from project() was being created, the compiler couldn’t invoke assign to a read only location. A simplified declaration of project() looks as follows:

template <int Size, typename Precision, typename Base>
Vector<Size-1,Precision> project(const Vector<Size, Precision, Base>& v);

What the project() function returns is not important; what is important is the use of the template parameter Precision in both the argument type and the return type. When I invoke operator[] on a const Matrix object, the returned vector’s precision inherits the const.

template <int Rows, int Cols, class Precision>
class Matrix {
...
Vector<Cols, const Precision, Slice> Matrix::operator[](int row) const;
};

When this vector is passed to the project() function above, the function tries to create and return a Vector<3, const double> which can only be initialized with a constexpr. Assigning to it via operator= or a constructor will not work to copy the data from the other vector.

There are several ways one can fix this, all of them involving removing the const qualifier from the Precision type on the returned vector.

It may seem like a simple solution would work:

template <int Size, typename Precision, typename Base, typename P2>
Vector<Size-1, P2> project(const Vector<Size, Precision, Base>& v);

Unfortunately, this requires the function be invoked as project<Size, Precision, Base, P2>(v); which is undesirable.

Solution #1

The first solution is simple, but tedious if you have several functions with similar signatures:

template <int Size, typename Precision, typename Base>
Vector<Size-1, typename std::remove_const<Precision>::type > 
project(const Vector<Size, Precision, Base>& v);

std::remove_const<T>::type is a type expression equal to the original type T, but with any const qualifiers removed. In this way, const double becomes simply double.

Solution #2

Another solution is to prevent the creation of a Vector object with a const precision, the idea that a non-slice vector with const data isn’t very useful — you can’t even construct one properly. Generally the only time you would actually want a vector with const data is when that data is pointing to some already existing area in memory (a slice).

Consider the following toy code for a vector class:

#define DECLARE_TYPES(T) \
    typedef typename std::remove_const<T>::type PlainType; \
    typedef const T ConstPlainType; \
    typedef typename std::remove_const<T>::type& ReferenceType; \
    typedef const T& ConstReferenceType

struct StackBase {
template <int Size, typename P>
class Layout { 
public:
    DECLARE_TYPES(P);
    PlainType data[Size];
};
};

struct SliceBase {
template <int Size, typename P>
class Layout {
public:
    P* data;
};
};

template <int Size, typename P = double, typename B = StackBase >
class Vector : public B::template Layout<Size, P> {
public:
    DECLARE_TYPES(P);
    using B::template Layout<Size, P>::data;

    ConstReferenceType operator[](int i) const { return data[i]; }
    ReferenceType operator[](int i) { return data[i]; }
};

When the Vector object is backed by owned storage (StackBase), the data is declared explicitly to be of a non-const type. Similarly, the return types of operator[] are defined to be the const and non-const reference types. The SliceBase, which handles references to un-owned data, retains the original templated type to allow pointing to constant data.

While this method prevents the creation of Vector objects with const owned data, it also means you don’t have to augment functions that interface with these objects to correct the return type.

For some reason, the messages in this example were uploaded in a way that caused them to be loaded in the wrong order on iOS 5.0.1. Since I run the mailserver myself, I took a look at the message files to see if I could deduce the cause of the issue. I noticed a series of messages on the mail server that looked like this:

1324697191.M91227P15574V000000000000CA00I0004B07D_556.hostname,S=5622:2,S
1324697192.M322096P15574V000000000000CA00I0004B07F_557.hostname,S=225691:2,RS
1324697196.M144018P15574V000000000000CA00I0004B081_558.hostname,S=7702:2,RS
1324697197.M715598P15574V000000000000CA00I0004B083_559.hostname,S=15741:2,S
1324697199.M327587P15574V000000000000CA00I0004B085_560.hostname,S=8744:2,RS

The received times of these messages, in the same order as listed above, are:

01/15/2010
01/09/2009
07/13/2010
02/21/2010
05/06/2010

It turns out that due to the messages in this example having a modification date that doesn’t match their receive timestamp the messages appear in the wrong order on an iOS device, where the mail application assumes the order of the messages it gets from the imap server is already sorted by date. This isn’t a problem with desktop mail clients — they simply fetch all the messages, sort them, and everything is fine. Several google searches on this subject yielded threads where people were trying to get their messages in the correct order and the suggested remedy was “sort them on the client side.”

To fix this, I wrote a perl script script to read the message headers, determine the receive time, and update the file name and modification date to match.

Use the script like this:

perl rename.pl cur/*

When you’re convinced it will do the right thing:

perl rename.pl cur/* --output-dir cur_renamed

After ensuring the rename was correct, I swapped the cur and cur_renamed directories, deleted the courierimapuiddb file, and restarted courier-imap. I also had to quit Mail.app on OS X and delete and read the mail account on the iOS device to get the messages to come in in the correct order.

I use the Google Authenticator app on iOS for 2-factor authentication into Google’s services. Recently, I was transitioning to a new phone after giving my existing one to my mom for Christmas. I did the standard backup -> restore plan which put most of my settings on my new device without issues. Fortunately, before I erased the old device, I made sure all my apps worked, including the authenticator.

Apparently, the data the authenticator app stores is not backed up for whatever reason, which means that instead of being able to generate the keys needed to access my accounts, the authenticator was prompting me to set up a new account. The smart folks over here recommend taking a screenshot of the QR code Google’s site gives you when you set up 2-factor authentication.

Questions:

To Google: Why doesn’t the authenticator back up its data? Seems this could be a nasty surprise for someone.
To Android users: Does this happen on Android as well?

From the algorithm detailed here I have implemented a clamped cubic spline class in C++. It is templated on the type of X and Y, allowing for use of scalar or vector types. It requires only that X and Y define the operators +, -, *, and /, and that Y have a constructor that takes a single scalar argument, initializing all elements to the supplied value.

Usage is very simple. For example, to interpolate a 2D location over time, try this:

#import "glm.hpp"
#import <vector>

std::vector<float> times;
std::vector<glm::vec2> points;
times.push_back(0);
points.push_back(glm::vec2(0));
times.push_back(.5f);
points.push_back(glm::vec2(-303, -572));
times.push_back(1);
points.push_back(glm::vec2(-250, -980));

/* Create the spline interpolating the position over time */
Spline<float, glm::vec2> sp(times, points);

/* Compute the interpolated position at time 0.75f */
glm::vec2 value(sp[.75f]);

The code for the spline class is below:

/* "THE BEER-WARE LICENSE" (Revision 42): Devin Lane wrote this file. As long as you retain 
 * this notice you can do whatever you want with this stuff. If we meet some day, and you
 * think this stuff is worth it, you can buy me a beer in return. */

#include <vector>
#include <iostream>

/** Templated on type of X, Y. X and Y must have operator +, -, *, /. Y must have defined
 * a constructor that takes a scalar. */
template <typename X, typename Y>
class Spline {
public:
    /** An empty, invalid spline */
    Spline() {}
    
    /** A spline with x and y values */
    Spline(const std::vector<X>& x, const std::vector<Y>& y) {
        if (x.size() != y.size()) {
            std::cerr << "X and Y must be the same size " << std::endl;
            return;
        }
        
        if (x.size() < 3) {
            std::cerr << "Must have at least three points for interpolation" << std::endl;
            return;
        }
        
        typedef typename std::vector<X>::difference_type size_type;
        
        size_type n = y.size() - 1;
        
        std::vector<Y> b(n), d(n), a(n), c(n+1), l(n+1), u(n+1), z(n+1);
        std::vector<X> h(n+1);

        l[0] = Y(1);
        u[0] = Y(0);
        z[0] = Y(0);
        h[0] = x[1] - x[0];
            
        for (size_type i = 1; i < n; i++) {
            h[i] = x[i+1] - x[i];
            l[i] = Y(2 * (x[i+1] - x[i-1])) - Y(h[i-1]) * u[i-1];
            u[i] = Y(h[i]) / l[i];
            a[i] = (Y(3) / Y(h[i])) * (y[i+1] - y[i]) - (Y(3) / Y(h[i-1])) * (y[i] - y[i-1]);
            z[i] = (a[i] - Y(h[i-1]) * z[i-1]) / l[i];
        }
            
        l[n] = Y(1);
        z[n] = c[n] = Y(0);
        
        for (size_type j = n-1; j >= 0; j--) {
            c[j] = z[j] - u[j] * c[j+1];
            b[j] = (y[j+1] - y[j]) / Y(h[j]) - (Y(h[j]) * (c[j+1] + Y(2) * c[j])) / Y(3);
            d[j] = (c[j+1] - c[j]) / Y(3 * h[j]);
        }
        
        for (size_type i = 0; i < n; i++) {
            mElements.push_back(Element(x[i], y[i], b[i], c[i], d[i]));
        }        
    }
    virtual ~Spline() {}
    
    Y operator[](const X& x) const {
        return interpolate(x);
    }
    
    Y interpolate(const X&x) const {
        if (mElements.size() == 0) return Y();
        
        typename std::vector<element_type>::const_iterator it;
        it = std::lower_bound(mElements.begin(), mElements.end(), element_type(x));
        if (it != mElements.begin()) {
            it--;
        }   
            
        return it->eval(x);
    }
    
    std::vector<Y> operator[](const std::vector<X>& xx) const {
        return interpolate(xx);
    }
    
    /* Evaluate at multiple locations, assuming xx is sorted ascending */
    std::vector<Y> interpolate(const std::vector<X>& xx) const {
        if (mElements.size() == 0) return std::vector<Y>(xx.size());
        
        typename std::vector<X>::const_iterator it;
        typename std::vector<element_type>::const_iterator it2;
        it2 = mElements.begin();
        std::vector<Y> ys;
        for (it = xx.begin(); it != xx.end(); it++) {
            it2 = std::lower_bound(it2, mElements.end(), element_type(*it));
            if (it2 != mElements.begin()) {
                it2--;
            }
                
            ys.push_back(it2->eval(*it));
        }

        return ys;
    }

protected:
    
    class Element {
    public:
        Element(X _x) : x(_x) {}
        Element(X _x, Y _a, Y _b, Y _c, Y _d)
        : x(_x), a(_a), b(_b), c(_c), d(_d) {}
        
        Y eval(const X& xx) const {
            X xix(xx - x);
            return a + b * xix + c * (xix * xix) + d * (xix * xix * xix);
        }
        
        bool operator<(const Element& e) const {
            return x < e.x;
        }
        bool operator<(const X& xx) const {
            return x < xx;
        }
        
        X x;
        Y a, b, c, d;
    };
            
    typedef Element element_type;
    std::vector<element_type> mElements;
};

The first time I played with monsters, I found the sound of a zombie’s “murrrrrrrr” in a dark, endless cavern to be frightening enough that I never wanted to hear it again. /shivers.

I find the first-person building experience to be very satisfying to the OCD urge within me that wants to make everything right. As all blocks are destroyable (with the exception of Bedrock), any reality can be created given enough time. I’m fond of using the different kinds of blocks to vary the aesthetics — even if the blocks type is not practical.

My favorite activity is to visualize my buildings at night, as I find the lighting of torches, lava, and glowstone to create a very pleasing effect. I also make frequent use of glass to provide a sense of openness and to allow light to mix between areas.

Here’s some screenshots of a large house on top of a hill that I’ve been working on.

The spacious master bedroom.

The kitchen has a large worktable, oven/stove, sink, and storage.

Sunset seen from one of the western bedrooms.

Front view of the house, looking down the walkway at the main entrance.

Lava provides heat and light to a central table in the living room, Kotatsu style.

The back side of the house is still in progress!

Contents Excluded

The contents of these paths are excluded, but the directories themselves are preserved as they are required for a successful restore. Remains the same as in Leopard.

/Volumes
/Network
/automount
/.vol
/tmp
/cores
/private/tmp
/private/Network
/private/tftpboot
/private/var/automount
/private/var/run
/private/var/tmp
/private/var/vm
/private/var/db/dhcpclient
/private/var/db/fseventsd
/Library/Caches
/Library/Logs
/System/Library/Caches
/System/Library/Extensions/Caches

These folders are excluded pre 10.5.something [Does anyone know when these came about?]

/private/var/log
/private/var/folders
/private/var/log/apache2
/private/var/log/cups
/private/var/log/fax
/private/var/log/ppp
/private/var/log/sa
/private/var/log/samba
/private/var/log/uucp
/private/var/spool

Paths Excluded

These directories and their contents are excluded completely. Remains the same as in Leopard.

/.Spotlight-V100
/.Trashes
/.fseventsd
/.hotfiles.btree
/Backups.backupdb
/Desktop DB
/Desktop DF
/Network/Servers
/Previous Systems
/Users/Shared/SC Info
/Users/Guest
/dev
/home
/net
/private/var/db/Spotlight
/private/var/db/Spotlight-V100

User Paths Excluded

These directories and their contents are excluded per-user. The path is relative to the user’s home folder.

Library/Application Support/SyncServices/data.version
Library/Caches
Library/Logs
Library/Mail/Envelope Index
Library/Mail/AvailableFeeds
Library/Mirrors
Library/PubSub/Database
Library/PubSub/Downloads
Library/PubSub/Feeds
Library/Safari/Icons.db
Library/Safari/WebpageIcons.db
Library/Safari/HistoryIndex.sk

File Contents Excluded

These directories are not themselves excluded, but the files in them are. The directories will be recreated on restore. Remains the same as in Leopard.

/private/var/log
/private/var/spool/cups
/private/var/spool/fax
/private/var/spool/uucp

There are situations, however, that can result in the inability of a subclass to do so. Consider NSURLRequest:

@interface NSURLRequest : NSObject <NSCoding, NSCopying, NSMutableCopying>

An immutable class, but one that implements NSMutableCopying, it responds directly to the -mutableCopyWithZone:(NSZone *)zone method that returns a mutable url request, an instance of NSMutableURLRequest. While this isn’t a problem in itself, it becomes an issue when this method is not re-implemented in NSMutableURLRequest.

@interface MyMutableURLRequest : NSMutableURLRequest {} @end

MyMutableURLRequest *request = [MyMutableURLRequest requestWithURL:url];
request = [request mutableCopy];