Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like WC_Shipping_Legacy_Flat_Rate often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use WC_Shipping_Legacy_Flat_Rate, and based on these observations, apply Extract Interface, too.
1 | <?php |
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16 | class WC_Shipping_Legacy_Flat_Rate extends WC_Shipping_Method { |
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17 | |||
18 | /** @var string cost passed to [fee] shortcode */ |
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19 | protected $fee_cost = ''; |
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20 | |||
21 | /** |
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22 | * Constructor. |
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23 | */ |
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24 | public function __construct() { |
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25 | $this->id = 'legacy_flat_rate'; |
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26 | $this->method_title = __( 'Flat Rate (Legacy)', 'woocommerce' ); |
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27 | $this->method_description = sprintf( __( '<strong>This method is deprecated in 2.6.0 and will be removed in future versions - we recommend disabling it and instead setting up a new rate within your <a href="%s">Shipping Zones</a>.</strong>', 'woocommerce' ), admin_url( 'admin.php?page=wc-settings&tab=shipping' ) ); |
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28 | $this->init(); |
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29 | |||
30 | add_action( 'woocommerce_update_options_shipping_' . $this->id, array( $this, 'process_admin_options' ) ); |
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31 | add_action( 'woocommerce_flat_rate_shipping_add_rate', array( $this, 'calculate_extra_shipping' ), 10, 2 ); |
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32 | } |
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33 | |||
34 | /** |
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35 | * Process and redirect if disabled. |
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36 | */ |
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37 | public function process_admin_options() { |
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38 | parent::process_admin_options(); |
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39 | |||
40 | if ( 'no' === $this->settings[ 'enabled' ] ) { |
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41 | wp_redirect( admin_url( 'admin.php?page=wc-settings&tab=shipping§ion=options' ) ); |
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42 | exit; |
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43 | } |
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44 | } |
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45 | |||
46 | /** |
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47 | * Return the name of the option in the WP DB. |
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48 | * @since 2.6.0 |
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49 | * @return string |
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50 | */ |
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51 | public function get_option_key() { |
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52 | return $this->plugin_id . 'flat_rate' . '_settings'; |
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53 | } |
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54 | |||
55 | /** |
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56 | * init function. |
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57 | */ |
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58 | public function init() { |
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59 | // Load the settings. |
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60 | $this->init_form_fields(); |
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61 | $this->init_settings(); |
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62 | |||
63 | // Define user set variables |
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64 | $this->title = $this->get_option( 'title' ); |
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65 | $this->availability = $this->get_option( 'availability' ); |
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66 | $this->countries = $this->get_option( 'countries' ); |
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67 | $this->tax_status = $this->get_option( 'tax_status' ); |
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68 | $this->cost = $this->get_option( 'cost' ); |
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69 | $this->type = $this->get_option( 'type', 'class' ); |
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70 | $this->options = $this->get_option( 'options', false ); // @deprecated in 2.4.0 |
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71 | } |
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72 | |||
73 | /** |
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74 | * Initialise Settings Form Fields. |
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75 | */ |
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76 | public function init_form_fields() { |
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77 | $this->form_fields = include( 'includes/settings-flat-rate.php' ); |
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78 | } |
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79 | |||
80 | /** |
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81 | * Evaluate a cost from a sum/string. |
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82 | * @param string $sum |
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83 | * @param array $args |
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84 | * @return string |
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85 | */ |
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86 | protected function evaluate_cost( $sum, $args = array() ) { |
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87 | include_once( WC()->plugin_path() . '/includes/libraries/class-wc-eval-math.php' ); |
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88 | |||
89 | $locale = localeconv(); |
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90 | $decimals = array( wc_get_price_decimal_separator(), $locale['decimal_point'], $locale['mon_decimal_point'] ); |
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91 | |||
92 | $this->fee_cost = $args['cost']; |
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93 | |||
94 | // Expand shortcodes |
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95 | add_shortcode( 'fee', array( $this, 'fee' ) ); |
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96 | |||
97 | $sum = do_shortcode( str_replace( |
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98 | array( |
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99 | '[qty]', |
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100 | '[cost]' |
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101 | ), |
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102 | array( |
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103 | $args['qty'], |
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104 | $args['cost'] |
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105 | ), |
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106 | $sum |
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107 | ) ); |
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108 | |||
109 | remove_shortcode( 'fee', array( $this, 'fee' ) ); |
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110 | |||
111 | // Remove whitespace from string |
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112 | $sum = preg_replace( '/\s+/', '', $sum ); |
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113 | |||
114 | // Remove locale from string |
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115 | $sum = str_replace( $decimals, '.', $sum ); |
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116 | |||
117 | // Trim invalid start/end characters |
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118 | $sum = rtrim( ltrim( $sum, "\t\n\r\0\x0B+*/" ), "\t\n\r\0\x0B+-*/" ); |
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119 | |||
120 | // Do the math |
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121 | return $sum ? WC_Eval_Math::evaluate( $sum ) : 0; |
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122 | } |
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123 | |||
124 | /** |
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125 | * Work out fee (shortcode). |
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126 | * @param array $atts |
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127 | * @return string |
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128 | */ |
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129 | public function fee( $atts ) { |
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130 | $atts = shortcode_atts( array( |
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131 | 'percent' => '', |
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132 | 'min_fee' => '' |
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133 | ), $atts ); |
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134 | |||
135 | $calculated_fee = 0; |
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136 | |||
137 | if ( $atts['percent'] ) { |
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138 | $calculated_fee = $this->fee_cost * ( floatval( $atts['percent'] ) / 100 ); |
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139 | } |
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140 | |||
141 | if ( $atts['min_fee'] && $calculated_fee < $atts['min_fee'] ) { |
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142 | $calculated_fee = $atts['min_fee']; |
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143 | } |
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144 | |||
145 | return $calculated_fee; |
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146 | } |
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147 | |||
148 | /** |
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149 | * calculate_shipping function. |
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150 | * |
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151 | * @param array $package (default: array()) |
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152 | */ |
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153 | public function calculate_shipping( $package = array() ) { |
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154 | $rate = array( |
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155 | 'id' => $this->id, |
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156 | 'label' => $this->title, |
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157 | 'cost' => 0, |
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158 | 'package' => $package, |
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159 | ); |
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160 | |||
161 | // Calculate the costs |
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162 | $has_costs = false; // True when a cost is set. False if all costs are blank strings. |
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163 | $cost = $this->get_option( 'cost' ); |
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164 | |||
165 | if ( $cost !== '' ) { |
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166 | $has_costs = true; |
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167 | $rate['cost'] = $this->evaluate_cost( $cost, array( |
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168 | 'qty' => $this->get_package_item_qty( $package ), |
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169 | 'cost' => $package['contents_cost'] |
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170 | ) ); |
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171 | } |
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172 | |||
173 | // Add shipping class costs |
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174 | $found_shipping_classes = $this->find_shipping_classes( $package ); |
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175 | $highest_class_cost = 0; |
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176 | |||
177 | foreach ( $found_shipping_classes as $shipping_class => $products ) { |
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178 | // Also handles BW compatibility when slugs were used instead of ids |
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179 | $shipping_class_term = get_term_by( 'slug', $shipping_class, 'product_shipping_class' ); |
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180 | $class_cost_string = $shipping_class_term && $shipping_class_term->term_id ? $this->get_option( 'class_cost_' . $shipping_class_term->term_id, $this->get_option( 'class_cost_' . $shipping_class, '' ) ) : $this->get_option( 'no_class_cost', '' ); |
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181 | |||
182 | if ( $class_cost_string === '' ) { |
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183 | continue; |
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184 | } |
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185 | |||
186 | $has_costs = true; |
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187 | $class_cost = $this->evaluate_cost( $class_cost_string, array( |
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188 | 'qty' => array_sum( wp_list_pluck( $products, 'quantity' ) ), |
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189 | 'cost' => array_sum( wp_list_pluck( $products, 'line_total' ) ) |
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190 | ) ); |
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191 | |||
192 | if ( $this->type === 'class' ) { |
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193 | $rate['cost'] += $class_cost; |
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194 | } else { |
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195 | $highest_class_cost = $class_cost > $highest_class_cost ? $class_cost : $highest_class_cost; |
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196 | } |
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197 | } |
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198 | |||
199 | if ( $this->type === 'order' && $highest_class_cost ) { |
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200 | $rate['cost'] += $highest_class_cost; |
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201 | } |
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202 | |||
203 | $rate['package'] = $package; |
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204 | |||
205 | // Add the rate |
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206 | if ( $has_costs ) { |
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207 | $this->add_rate( $rate ); |
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208 | } |
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209 | |||
210 | /** |
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211 | * Developers can add additional flat rates based on this one via this action since @version 2.4. |
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212 | * |
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213 | * Previously there were (overly complex) options to add additional rates however this was not user. |
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214 | * friendly and goes against what Flat Rate Shipping was originally intended for. |
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215 | * |
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216 | * This example shows how you can add an extra rate based on this flat rate via custom function: |
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217 | * |
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218 | * add_action( 'woocommerce_flat_rate_shipping_add_rate', 'add_another_custom_flat_rate', 10, 2 ); |
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219 | * |
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220 | * function add_another_custom_flat_rate( $method, $rate ) { |
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221 | * $new_rate = $rate; |
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222 | * $new_rate['id'] .= ':' . 'custom_rate_name'; // Append a custom ID. |
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223 | * $new_rate['label'] = 'Rushed Shipping'; // Rename to 'Rushed Shipping'. |
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224 | * $new_rate['cost'] += 2; // Add $2 to the cost. |
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225 | * |
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226 | * // Add it to WC. |
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227 | * $method->add_rate( $new_rate ); |
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228 | * }. |
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229 | */ |
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230 | do_action( 'woocommerce_flat_rate_shipping_add_rate', $this, $rate ); |
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231 | } |
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232 | |||
233 | /** |
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234 | * Get items in package. |
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235 | * @param array $package |
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236 | * @return int |
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237 | */ |
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238 | public function get_package_item_qty( $package ) { |
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239 | $total_quantity = 0; |
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240 | foreach ( $package['contents'] as $item_id => $values ) { |
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241 | if ( $values['quantity'] > 0 && $values['data']->needs_shipping() ) { |
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242 | $total_quantity += $values['quantity']; |
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243 | } |
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244 | } |
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245 | return $total_quantity; |
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246 | } |
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247 | |||
248 | /** |
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249 | * Finds and returns shipping classes and the products with said class. |
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250 | * @param mixed $package |
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251 | * @return array |
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252 | */ |
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253 | public function find_shipping_classes( $package ) { |
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254 | $found_shipping_classes = array(); |
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255 | |||
256 | foreach ( $package['contents'] as $item_id => $values ) { |
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257 | if ( $values['data']->needs_shipping() ) { |
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258 | $found_class = $values['data']->get_shipping_class(); |
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259 | |||
260 | if ( ! isset( $found_shipping_classes[ $found_class ] ) ) { |
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261 | $found_shipping_classes[ $found_class ] = array(); |
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262 | } |
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263 | |||
264 | $found_shipping_classes[ $found_class ][ $item_id ] = $values; |
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265 | } |
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266 | } |
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267 | |||
268 | return $found_shipping_classes; |
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269 | } |
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270 | |||
271 | /** |
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272 | * Adds extra calculated flat rates. |
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273 | * |
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274 | * @deprecated 2.4.0 |
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275 | * |
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276 | * Additonal rates defined like this: |
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277 | * Option Name | Additional Cost [+- Percents%] | Per Cost Type (order, class, or item). |
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278 | */ |
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279 | public function calculate_extra_shipping( $method, $rate ) { |
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280 | if ( $this->options ) { |
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281 | $options = array_filter( (array) explode( "\n", $this->options ) ); |
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282 | |||
283 | foreach ( $options as $option ) { |
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284 | $this_option = array_map( 'trim', explode( WC_DELIMITER, $option ) ); |
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285 | if ( sizeof( $this_option ) !== 3 ) { |
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286 | continue; |
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287 | } |
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288 | $extra_rate = $rate; |
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289 | $extra_rate['id'] = $this->id . ':' . urldecode( sanitize_title( $this_option[0] ) ); |
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290 | $extra_rate['label'] = $this_option[0]; |
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291 | $extra_cost = $this->get_extra_cost( $this_option[1], $this_option[2], $rate['package'] ); |
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292 | if ( is_array( $extra_rate['cost'] ) ) { |
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293 | $extra_rate['cost']['order'] = $extra_rate['cost']['order'] + $extra_cost; |
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294 | } else { |
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295 | $extra_rate['cost'] += $extra_cost; |
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296 | } |
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297 | |||
298 | $this->add_rate( $extra_rate ); |
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299 | } |
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300 | } |
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301 | } |
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302 | |||
303 | /** |
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304 | * Calculate the percentage adjustment for each shipping rate. |
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305 | * |
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306 | * @deprecated 2.4.0 |
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307 | * @param float $cost |
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308 | * @param float $percent_adjustment |
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309 | * @param string $percent_operator |
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310 | * @param float $base_price |
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311 | * @return float |
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312 | */ |
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313 | public function calc_percentage_adjustment( $cost, $percent_adjustment, $percent_operator, $base_price ) { |
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314 | if ( '+' == $percent_operator ) { |
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315 | $cost += $percent_adjustment * $base_price; |
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316 | } else { |
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317 | $cost -= $percent_adjustment * $base_price; |
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318 | } |
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319 | return $cost; |
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320 | } |
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321 | |||
322 | /** |
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323 | * Get extra cost. |
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324 | * |
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325 | * @deprecated 2.4.0 |
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326 | * @param string $cost_string |
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327 | * @param string $type |
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328 | * @param array $package |
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329 | * @return float |
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330 | */ |
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331 | public function get_extra_cost( $cost_string, $type, $package ) { |
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332 | $cost = $cost_string; |
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333 | $cost_percent = false; |
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334 | $pattern = |
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335 | '/' . // start regex |
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336 | '(\d+\.?\d*)' . // capture digits, optionally capture a `.` and more digits |
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337 | '\s*' . // match whitespace |
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338 | '(\+|-)' . // capture the operand |
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339 | '\s*'. // match whitespace |
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340 | '(\d+\.?\d*)'. // capture digits, optionally capture a `.` and more digits |
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341 | '\%/'; // match the percent sign & end regex |
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342 | if ( preg_match( $pattern, $cost_string, $this_cost_matches ) ) { |
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343 | $cost_operator = $this_cost_matches[2]; |
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344 | $cost_percent = $this_cost_matches[3] / 100; |
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345 | $cost = $this_cost_matches[1]; |
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346 | } |
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347 | switch ( $type ) { |
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348 | case 'class' : |
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349 | $cost = $cost * sizeof( $this->find_shipping_classes( $package ) ); |
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350 | break; |
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351 | case 'item' : |
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352 | $cost = $cost * $this->get_package_item_qty( $package ); |
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353 | break; |
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354 | } |
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355 | if ( $cost_percent ) { |
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356 | switch ( $type ) { |
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357 | case 'class' : |
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358 | $shipping_classes = $this->find_shipping_classes( $package ); |
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359 | foreach ( $shipping_classes as $shipping_class => $items ){ |
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360 | foreach ( $items as $item_id => $values ) { |
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361 | $cost = $this->calc_percentage_adjustment( $cost, $cost_percent, $cost_operator, $values['line_total'] ); |
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362 | } |
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363 | } |
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364 | break; |
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365 | case 'item' : |
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366 | foreach ( $package['contents'] as $item_id => $values ) { |
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367 | if ( $values['data']->needs_shipping() ) { |
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368 | $cost = $this->calc_percentage_adjustment( $cost, $cost_percent, $cost_operator, $values['line_total'] ); |
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369 | } |
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370 | } |
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371 | break; |
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372 | case 'order' : |
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373 | $cost = $this->calc_percentage_adjustment( $cost, $cost_percent, $cost_operator, $package['contents_cost'] ); |
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374 | break; |
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375 | } |
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376 | } |
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377 | return $cost; |
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378 | } |
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379 | } |
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380 |