The Road to PHP Master (1)_PHP Tutorial

PHP is an efficient network programming language. Due to its advantages of flexible writing and fast running, it has quickly become the preferred language for Web programmers. An authoritative survey not long ago showed that 31.6% of websites now use PHP as the main server-side programming language.
However, it is not easy to become a PHP programming master. It is not as many people imagine, as long as you can quickly write a few simple codes to solve a complex problem, you are a PHP programming master. A real PHP master also needs to consider many other issues. The following three guidelines are the guidelines that a mature PHP programmer should first follow in programming.
1. Laziness is golden
2. Write beautiful code
3. Pursue the speed of the program, not the speed of programming
1. Laziness is golden
Are you a lazy programmer? ? This idea is so strange! Because probably the busiest people in the world are computer programmers. But it is precisely because programmers are too busy that they should learn to be lazy when programming.
For a programmer, there are two lazy ways: First, boldly use other people’s ready-made program codes and integrate these codes into your own programs or projects. The second is to write some useful codes to build a function library, which can be easily used when writing programs in the future. This saves a lot of repetitive work and naturally makes you less lazy.
These two lazy methods are very suitable for PHP programmers.
First of all, PHP is a language born and grown in a free and open environment. There are thousands of programmers around the world who have been constantly striving for the perfection of PHP, and they are also willing to share their ingenuity and the code they write with others. You can find a lot of excellent program code every day from some PHP websites, mailing lists, and news groups. By saying this, I am not encouraging you to wait all day for others to write code for you, but you can "stand on the shoulders of great men" and fully promote the "use doctrine". Smart application of other people's program codes can save you a lot of money. time. Secondly, in PHP, you can easily build your own function library, which can save you a lot of trouble when writing programs in the future.
The author below introduces several common functions to you. Some of these functions come from some open source projects on the Internet, and some are selected from the mailing list. If you can add them to your own library, sooner or later you will find yourself benefiting from them.
1. Universal database processing function
Compared with other CGI functions, one of the advantages of PHP is that it has very powerful database processing capabilities. However, in PHP, some specific functions are used to handle different databases, and there is a lack of general database processing functions. This greatly reduces the portability of program code, which also brings a lot of inconvenience to beginner programming friends.
On the Internet, many programmers have solved this problem by encapsulating classes. They wrote unified functions to handle any popular database - whether it is Mysql, which is popular in the Linux world, or SqlServer, which is widely popular on Windows platforms. Personally, I like to use these functions very much, because you can directly use some simple functions such as "query" and "next_record" without having to consider complicated things such as database connections and database handles, let alone Consider what database you are using.
If you need these functions, you can get them by visiting the following URLs:
http://phplib.netuse.de/
http://phpclasses.UpperDesign.com/browse.html /package/20
http://phpdb.linuxbox.com/
2. Variable debugging function
Debugging PHP programs has always been a headache. It is not like high-level languages ​​​​such as VB. That way there is an integrated compilation and debugging environment, unlike Perl which can be run directly in a Linux or DOS environment. In fact, we can complete the debugging of PHP by flexibly using the echo statement.
The following functions allow you to check the type and value of any variable in the program at any time.
  function ss_array_as_string (＆＄array, ＄column = 0) {
  ＄str = "Array(
n";
  while(list(＄var, ＄val) = each(＄array)){
  for (＄i = 0; ＄i < ＄column＋1; ＄i＋＋){
  ＄str .= "＆nbsp;＆nbsp;＆nbsp;＆nbsp;";
  }
  ＄str .= ＄var. ==> ;
  ＄str .= ss_as_string(＄val, ＄column＋1)."
n";
  }
  for (＄i = 0; ＄i < ＄column; ＄i＋＋){
  ＄str .= "＆nbsp;＆nbsp;＆nbsp;＆nbsp;";
  }
  return ＄str.);
  }
  function ss_object_as_string (＆＄object, ＄column = 0) {
   if (empty(＄object－>classname)) {
  return "＄object";
  }
  else {
  ＄str = ＄object－>classname."(
n";
  while (list(,＄var) = each(＄object－>persistent_slots)) {
  for (＄i = 0; ＄i < ＄column; ＄i＋＋){
  ＄str .= "＆nbsp;＆nbsp;＆nbsp;＆nbsp;";
  }
  global ＄＄var;
  ＄str .= ＄var. ==> ;
  ＄str .= ss_as_string(＄＄var, column＋1)."
n";
  }
  for (＄i = 0; ＄i < ＄column; ＄i＋＋){
  ＄str .= "＆nbsp;＆nbsp;＆nbsp;＆nbsp;";
  }
  return ＄str.);
  }
  }
  function ss_as_string (＆＄thing, ＄column = 0) {
  if (is_object(＄thing)) {
  return ss_object_as_string(＄thing, ＄column);
  }
  elseif (is_array(＄thing)) {
  return ss_array_as_string(＄thing, ＄column);
  }
  elseif (is_double(＄thing)) {
  return "Double(".＄thing.")";
  }
  elseif (is_long(＄thing)) {
  return "Long(".＄thing.")";
  }
  elseif (is_string(＄thing)) {
  return "String(".＄thing.")";
  }
  else {
  return "Unknown(".＄thing.")";
  }
  }
  需要的时候，在程序中简单地加入下面的一条代码即可查看程序中的所使用的变量（包括数组和对象）的类型和值：
  echo ss_as_string(＄my_variable);
  使用下面的语句，我们可以直接查看程序中所有的变量的值：
  echo ss_as_string(＄GLOBALS);
  3. 控制Log信息的函数
  调试PHP程序的另外一种重要的方法就是查看Log信息。如果能够方便地控制Log信息的级别以及Log信息的显示内容，将会给程序调试带来更多的便利。下面的几个函数可以方便地实现这个功能。
  ＄ss_log_level = 0;
  ＄ss_log_filename = /tmp/ss－log;
  ＄ss_log_levels = array(
  NONE => 0,
  ERROR => 1,
  INFO => 2,
  DEBUG => 3);
  function ss_log_set_level (＄level = ERROR) {
  global ＄ss_log_level;
  ＄ss_log_level = ＄level;
  }
  function ss_log (＄level, ＄message) {
  global ＄ss_log_level, ＄ss－log－filename;
  if (＄ss_log_levels[＄ss_log_level] < ＄ss_log_levels[＄level]) {
  // 不显示Log信息
  return false;
  }
  ＄fd = fopen(＄ss_log_filename, "a＋");
  fputs(＄fd, ＄level. － [.ss_timestamp_pretty().] － .＄message."n");
  fclose(＄fd);
  return true;
  }
  function ss_log_reset () {
  global ＄ss_log_filename;
  @unlink(＄ss_log_filename);
  }
  在上面的函数中，有四个Log级别变量。运行PHP程序时，只有当Log的级别低于预设的级别值时，Log信息才可以被记录和显示出来。例如，在程序中加入如下的一条语句：
  ss_log_set_level(INFO);
  那么，运行PHP程序时，只有ERROR和INFO级别的LOG信息才能被记录和显示出来，DEBUG级的信息则被忽略了。In addition, we can also set the displayed information content. The statements are as follows:
ss_log(ERROR, "testing level ERROR");
ss_log(INFO, "testing level INFO");
ss_log(DEBUG, "testing level DEBUG");
You can also use the following statement to clear the LOG information at any time:
ss_log_reset();
4. Speed ​​test function

In order to optimize the code , we need a method that can test the running time of the code to choose the optimal code. The following function can test the time required to run the code:
function ss_timing_start (＄name = default) {
global ＄ss_timing_start_times;
＄ss_timing_start_times[＄name] = explode( , microtime());
}
function ss_timing_stop (＄name = default) {
global ＄ss_timing_stop_times;
＄ss_timing_stop_times[＄name] = explode(, microtime());
}
function ss_timing_current ( ＄name = default) {
global ＄ss_timing_start_times, ＄ss_timing_stop_times;
if (!isset(＄ss_timing_start_times[＄name])) {
return 0;
}
if (!isset (＄ss_timing_stop_times[＄name])) {
＄stop_time = explode(, microtime());
}
else {
＄stop_time = ＄ss_timing_stop_times[＄name];
}
＄current = ＄stop_time[1] - ＄ss_timing_start_times[＄name][1];
＄current += ＄stop_time[0] - ＄ss_timing_start_times[＄name][0];
return ＄ current;
}
Now you can easily check the execution time of any piece of code. We can even use multiple timers at the same time. We only need to set different parameters as timers when using the above functions. The name will do.
5. Debugging and optimizing database operations
For databases, running speed is crucial. Although many books and articles teach methods for running databases quickly, all methods must be tested in practice. Next, we will combine the query() function in the PHPLib function library and the functions introduced above to write a new query() function. Compared with the original function, this function adds a running time monitoring function.
function query(＄Query_String, ＄halt_on_error = 1) {
＄this－>connect();
ss_timing_start();
＄this－>Query_ID = @mysql_query(＄Query_String, ＄this－>Link_ID);
ss_timing_stop();
ss_log(INFO, ss_timing_current(). Secs - .＄Query_String);
＄this－>Row = 0;
＄this ->Errno = mysql_errno();
＄this－>Error = mysql_error();
if (＄halt_on_error && !＄this－>Query_ID) {
＄this－>halt( "Invalid SQL: ".＄Query_String);
}
return ＄this－>Query_ID;
}(To be continued)

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