當傳遞給lynx的URL無效時，如何設置默認操作？

Question

我的目標是編寫一個小的bash腳本，將給定PHP函數的手冊頁的內容輸出到終端。 我當前的腳本（ pfunc ）如下：

#!/bin/bash

if [ -z "$1" ]

    then
        echo
        echo "No function specified"
        echo
        echo "pfunc command syntax: pfunc <function>"
        echo        
        echo "Example: pfunc func_get_args"
        echo
        exit 1

    else    
        func=$1
        url="http://php.net/$func"
        contents=$(lynx -dump $url) 

        clear
        awk -v a="$contents" -v b="$func" 'BEGIN{gsub(/\"\n\"/, "\"\\n\"", a); print substr(a, index(a, b" —"), index(a, "See Also") - index(a, b" —"))}' 

fi

到目前為止，它正在按預期工作：

me@mybox:~$ pfunc rand | head -17

產生

rand — Generate a random integer

Description

   int rand ( void )
   int rand ( int $min , int $max )

   If called without the optional min, max arguments rand() returns a
   pseudo-random integer between 0 and [74]getrandmax(). If you want a
   random number between 5 and 15 (inclusive), for example, use rand(5,
   15).

     Note: On some platforms (such as Windows), [75]getrandmax() is only
     32767. If you require a range larger than 32767, specifying min and
     max will allow you to create a range larger than this, or consider
     using [76]mt_rand() instead.

每當傳遞無效的URL時，我都會打印一條消息，例如“ PHP中不存在該函數”之類的消息，而不是靜默返回命令提示符。 誰能提供一些關於如何執行此操作的見解？ 提前致謝。

Answer 1

無論查詢是否成功，PHP.net都會返回成功的響應，因此您無法像在行為良好的網站中那樣檢查HTTP狀態代碼。

您可以改為使用kludge：

#!/bin/bash

if [ -z "$1" ]

    then
        echo
        echo "No function specified"
        echo
        echo "pfunc command syntax: pfunc <function>"
        echo     
        echo "Example: pfunc func_get_args"
        echo
        exit 1

    else 
        func=$1
        url="http://php.net/$func"
        contents=$(lynx -dump $url)

        if [[ $contents == *"doesn't exist. Closest matches"* ]]
        then 
            echo "No such function" >&2
        else
            clear
            awk -v a="$contents" -v b="$func" 'BEGIN{gsub(/\"\n\"/, "\"\\n\"", a); print substr(a, index(a, b" —"), index(a, "See Also") - index(a, b" —"))}'
        fi
fi

Answer 2

我會根據您的腳本做什么：

#!/bin/bash

if [ -z "$1" ]

    then
        echo
        echo "No function specified"
        echo
        echo "pfunc command syntax: pfunc <function>"
        echo        
        echo "Example: pfunc func_get_args"
        echo
        exit 1

    else
        func=$1
        url="http://php.net/$func"
        contents=$(lynx -dump $url)
        if [[ $contents =~ $func[[:space:]]+doesn.t[[:space:]]+exist.[[:space:]]+Closest[[:space:]]+matches ]]
        then
            echo >&2 "php.net don't have a page for $func"
            exit 1
        fi
        clear
        awk -v a="$contents" -v b="$func" 'BEGIN{gsub(/\"\n\"/, "\"\\n\"", a); print substr(a, index(a, b" —"), index(a, "See Also") - index(a, b" —"))}'
fi

Answer 3

您可以解析lynx的響應（或其他方式，如wget，curl，lwp-request）以確定該函數是否不存在。

lwp-request的示例：

[neumann@MacBookPro ~]$ GET "http://php.net/$func"|grep "<b>$func</b> doesn'\t exist"
 <b>toto</b> doesn't exist. Closest matches:
[neumann@MacBookPro ~]$ func=preg_match
[neumann@MacBookPro ~]$ GET "http://php.net/$func"|grep "<b>$func</b> doesn'\t exist"
[neumann@MacBookPro ~]$ 

因此，您可以嘗試執行以下操作：

existFunction(){
    lwp-request -mget "http://php.net/$1"|grep "<b>$1</b> doesn'\t exist" >/dev/null || echo "1"
}

if [[ $(existFunction $1) = 1 ]]; then
    echo "YES"
fi

注意：GET是“ lwp-request -mget”的別名。