[李景山php]每天laravel-20161011|Validator.php-11

    /**
     * Given two date/time strings, check that one is after the other.
     *
     * @param  string  $format
     * @param  string  $before
     * @param  string  $after
     * @return bool
     */
    protected function checkDateTimeOrder($format, $before, $after)
    {
        $before = $this->getDateTimeWithOptionalFormat($format, $before);// format it

        $after = $this->getDateTimeWithOptionalFormat($format, $after);// format after

        return ($before && $after) && ($after > $before);// a big logic
    }// get two date/time strings, check that one is after the other.

    /**
     * Get a DateTime instance from a string.
     *
     * @param  string  $format
     * @param  string  $value
     * @return \DateTime|null
     */
    protected function getDateTimeWithOptionalFormat($format, $value)
    {//Get a DateTime instance from a sting.
        $date = DateTime::createFromFormat($format, $value);//Date::createFromFormat

        if ($date) {// if date
            return $date;
        }

        try {// return new DateTime
            return new DateTime($value);
        } catch (Exception $e) {
            // do nothing
        }
    }

    /**
     * Validate that an attribute is a valid timezone.
     *
     * @param  string  $attribute
     * @param  mixed   $value
     * @return bool
     */
    protected function validateTimezone($attribute, $value)
    {
        try {
            new DateTimeZone($value);
        } catch (Exception $e) {
            return false;
        }

        return true;
    }//validate timezone

    /**
     * Get the date format for an attribute if it has one.
     *
     * @param  string  $attribute
     * @return string|null
     */
    protected function getDateFormat($attribute)
    {
        if ($result = $this->getRule($attribute, 'DateFormat')) {
            return $result[1][0];
        }
    }// Get the date format from an attribute if it has one.

    /**
     * Get the validation message for an attribute and rule.
     *
     * @param  string  $attribute
     * @param  string  $rule
     * @return string
     */
    protected function getMessage($attribute, $rule)
    {
        $lowerRule = Str::snake($rule);// use snake method to get this you  want

        $inlineMessage = $this->getInlineMessage($attribute, $lowerRule);// get message

        // First we will retrieve the custom message for the validation rule if one
        // exists. If a custom validation message is being used we'll return the
        // custom message, otherwise we'll keep searching for a valid message.
        if (! is_null($inlineMessage)) {
            return $inlineMessage;
        }// if it is a good message

        $customKey = "validation.custom.{$attribute}.{$lowerRule}";// this can  get a good key

        $customMessage = $this->getCustomMessageFromTranslator($customKey);

        // First we check for a custom defined validation message for the attribute
        // and rule. This allows the developer to specify specific messages for
        // only some attributes and rules that need to get specially formed.
        if ($customMessage !== $customKey) {
            return $customMessage;
        }// return the custom message

        // If the rule being validated is a "size" rule, we will need to gather the
        // specific error message for the type of attribute being validated such
        // as a number, file or string which all have different message types.
        elseif (in_array($rule, $this->sizeRules)) {
            return $this->getSizeMessage($attribute, $rule);
        }// specific error

        // Finally, if no developer specified messages have been set, and no other
        // special messages apply for this rule, we will just pull the default
        // messages out of the translator service for this validation rule.
        $key = "validation.{$lowerRule}";

        if ($key != ($value = $this->translator->trans($key))) {
            return $value;
        }// just message

        return $this->getInlineMessage(
            $attribute, $lowerRule, $this->fallbackMessages
        ) ?: $key;// return key
    }