如何从命名空间元素中检索属性

Question

我试图从这个RSS feed中的url元素获取<media:content>属性：

https://news.google.com/rss/search?q=test&as_qdr=w1&scoring=n&num=100&hl=en-CA&gl=CA&ceid=CA:en

这是我到目前为止所拥有的：

$feed_url = "https://news.google.com/rss/search?q=test&as_qdr=w1&scoring=n&num=100&hl=en-CA&gl=CA&ceid=CA:en";

$rss = file_get_contents($feed_url);
$rss = new SimpleXMLElement($rss);
$items = $rss->channel->item; 

foreach ($items as $item) {
    print_r($item);
    echo "<hr>";
}

此代码适用于除名称中带分号的元素之外的所有元素，如<media:content>或<dc:contributor>。如果我在浏览器中打开XML提要，我可以看到我正在寻找的标签：

<media:content url="https://lh6.googleusercontent.com/proxy/nxX8kqpFKSDvYg_bf_QrdsS0PYNMFPGspYmTlZlIo0IzyyhYhURxQc5nrpnzfrNBZkWQywioGXdPclazSIEwiz5wklsBePHOCft9qdHl2EmqIES_SMl5orim2xM2eHYalvIgFFeGYvp7cQaCQpKAObhPGQ--diqZg4Io3MSW8f6PXlRAbUcPvpDxB-KRqBj53bbROhoUYuqxkA=-w150-h150-c" medium="image" width="150" height="150"/>
</item>

我试过其他线程的各种解决方案，但它对我不起作用。例：

$xml_object = $rss->channel->item[0];
$ns_media = $xml_object->children('http://search.yahoo.com/mrss/');

我不知道我做错了什么，所以我会感激一些帮助

Answer 1

你错过了对attributes()实例的SimpleXMLElement方法的调用：

foreach ($items as $item) {
  $media_content_url = $item->children('http://search.yahoo.com/mrss/')->attributes()->url;
  // ...
}

Answer 2

我不熟悉SimpleXML，但这对于DomDocument很简单：

$feed_url = "https://news.google.com/rss/search?q=test&as_qdr=w1&scoring=n&num=100&hl=en-CA&gl=CA&ceid=CA:en";

$rss = file_get_contents($feed_url);
$dom = new DomDocument;
$dom->loadXML($rss);
$nodes = $dom->getElementsByTagNameNS("http://search.yahoo.com/mrss/", "content");
foreach ($nodes as $node) {
    printf("%s\n", $node->getAttribute("url"));
}

输出：

https://lh6.googleusercontent.com/proxy/m7yanlDdWIjGc1XmsY6AHB5DqqJcgSe1Z7vs9DUC5NbD-FfQqJzEY8uIadNckLJFu7O6rcuh4W-CsXRg2vjr_KLOWhwNG5shhfdetcUkY5dMHa0uN1GBC5iY0svkP-Wxcm7JJ_kJMh6sctcvJ5Hfbb2Vor8KPlnYXUk_Y3jxYeCgmDBTqeRKwQ1pTMtWtJ_7fK5P5PSdKQKjUNnfVODZjHg_c4PwFWw3Cw=-w150-h150-c
https://lh3.googleusercontent.com/proxy/j7vDbXvscxGVLF8xo2DGkEgmgyQ9-u5vE0RWJjmAp84xOuy4v-Ff6cHADsLiC2Zd2KE7s04sCgtT_WNx4K5vxjDw_jbFRwQhlBgpL-YdXMgvDgakxzx8xWDO5bdpHaVssEGXgkxCnXnHXBRgb67vXeY6XnbgeEp7Fe5ohK1fpyk_hE3IYGyHdJnTxiH_=-w150-h150-c
https://lh6.googleusercontent.com/proxy/nxX8kqpFKSDvYg_bf_QrdsS0PYNMFPGspYmTlZlIo0IzyyhYhURxQc5nrpnzfrNBZkWQywioGXdPclazSIEwiz5wklsBePHOCft9qdHl2EmqIES_SMl5orim2xM2eHYalvIgFFeGYvp7cQaCQpKAObhPGQ--diqZg4Io3MSW8f6PXlRAbUcPvpDxB-KRqBj53bbROhoUYuqxkA=-w150-h150-c
https://lh3.googleusercontent.com/proxy/PbDyKTNQAyxkLNnyQFm00dHkNyKoASc3zKJjw7tjRtfmebHfbP_Ov_5RfcsG1RL8gyFaMSvVltd7IQJns6x_N_thPQTWz7E3ER0RlqLhZBYjmM-cp9xUkCdICiFyfkY0XGx-xGSh6zq5C_SpuzAxCVdhoOkqW4Lz_kyw-KN1fUJB6b8VgDGFvssIfmurSm3qCdJYeFJAx7x6lh_NQS1GNeNdbVBf0RoE2jiZfK6SYgFCX2s9KifQ7Sld_0plNrvTyW6VSR9D0AEwlBClWXNfoMmB_NYl4j03ELoUIjB0fRpUxV7YAqiIC1nSxqn92Q=-w150-h150-c
https://lh6.googleusercontent.com/proxy/DcJhP_BX_r7IbiwFgYt7MOL8RKQMizjCEWAn4YBcWdDy-PYOncpb_PrDZ0H5cMlxSFk9X8SQz5WEAX1xJRV4RWBiPwSH6uDJr7bt1Dh4H7MyYAaB_66BnASNA-fw0pszLPYEgfkwZsRyEZNT045MRYXA3Q=-w150-h150-c
https://lh5.googleusercontent.com/proxy/ECDRkzc4AO3OP1V0PNEVw1OhBYwuDRJVdDzF9lFNW34D8aNO8s54aWJfuR_LhDz-wKCRRvS64ggZnsg2UkCE5EYJghnBkQlpmwktgFYcKW0OnXP_-Ynh37EHR9nG9lyRoM1-3ebj=-w150-h150-c
https://lh6.googleusercontent.com/proxy/9xL1YVQyHg2mzitNgeiHRkjq_vJBxmOb0iAb1bBfJcqFLlWOJWkzRmLYrc9-hmK4nGcLnFfLMEb-bTnZmlWRM72_9ibysFUU_z-77ZK5PhX-f8vfIoWp=-w150-h150-c
https://lh5.googleusercontent.com/proxy/FcDG9_8xHTVUP2uHZ6cMAnIAdDxd-Kg29IksHUEDJCX8_mjTd2voG8BITnqpPEXKtFEImDogPfJfHNlqJr7X2I0VHlkesJvRnE2D-aLRxiNJfc2Lh6WIb0PrRy2nluPe6IJOhUulh0AzZ8JXJVBPgYnfeifItdhBsCTz7QtKGN4DbLZzDAVRL28mHNzaFBlCjCMGyhrbR3jmmlLWqj5K6lbfdoS0jxbLDKkNY8ywVq61rua1YHe-J6ZOY40ESL_0hf27KTgIJFSNq99yGX2sMw=-w150-h150-c
https://lh3.googleusercontent.com/proxy/ciJtTGr7RBlyJD2JGS-Ps4OUOcHxph6Csa1RCJOhcIjjqnjMHnqDzBU2MwEBoieNz37zmC69cPcoUi9696CfpMYh_cry5O6xmTT-1BnlyJhGMTeDR2mIbf3-3VEJ5YsNHmyozvClGvbR6_ZOaMgH0w3AWwf_bZppmqXp7Bul8rXDOkIDMeHrmKCpQcJff-lAbV7hnud3h0JH0--7zw5wCCOj57dNwIA=-w150-h150-c
https://lh5.googleusercontent.com/proxy/nyoQUYC-IPq8Td_GPYc60euyS5cgKwUk7ta1ISJl9wafgrGt1HkhVtPSpoO36KZl_8em4B9bBuP_OXmR0RZlGk1yLwcfAK42NknrGy5H0bLwJqouJ0sE0a21EwardDsVGe1XhGXETO92NfSG2Tikpl9pUFLiJEE-ySdL2d5CK9LA82P4DG6FM5eW=-w150-h150-c
https://lh3.googleusercontent.com/proxy/F2QF_T-xeBkwMyMljtdxwaXMQmNvyG9YCv2QmdBBSmNCe6okG7AIuElWuXXI45IjTA8fuyEZbeGEHBJdWIeyxcjiwapXjzAIxm1lxrmMdzLgJyD4C867KZtcTS1NTWyJebHY4u3gBQ2Z=-w150-h150-c
https://lh4.googleusercontent.com/proxy/rbbBxl7QWG4BBIlsvJUIfL3fr8j4f7L_LoRc3NvfWcNOGT7oX7U1_CpJ71oE04TD0Ax75WmDJrlBQNYPGcsQnOid874Z6P3nwNpdNtZlytX_6FlXqefr58IQ3fB-sivfI20EmQVnRfaBXUozjpHbjW225jeI1hxWc1U15MC_rMuJryLEC_CV4OLg=-w150-h150-c
https://lh5.googleusercontent.com/proxy/7TRaIMikpkiHsWKNenXItiKUUSnRhEl92XSOmDHl828VWobr_M8crMxMLvfG9BDbVc4SioxINBmDyDLhxyHiLlk_c_-6ocsm6ATjrUbWHuc-FTba=-w150-h150-c
https://lh5.googleusercontent.com/proxy/VDXcSNdIqLdhl6IFXyQlwOlzDlhPGaPTOWN0XMuX_DHozxXowzuQMWGAnFNIizgXavLZ5rVcw9rGl7NWTHMyRboJVqjzRRtoOs1GJCb0dylyUsHSt5qUSOZULdyBDPkW6HXVDHHyR40EeR4CS9nOX0M=-w150-h150-c
https://lh5.googleusercontent.com/proxy/YlbnCDloJxYZBVFhx-k2JZzYzFhcBA6DMAim5QTgNoyB4-Q_8DjgR2-JV73ARnUmpROHYfdZiKwfEUCdPB7tUSJ-uJuSRFgfQ_t8CV6rQ8zAXiIKOuoNO20AMArh5NXKr99nP_FoiOLf6mIEJw--URXUP0Tg4-i7bCXXdIPIvVpWNaDxKesNa1MRzIWkzHnYoGuy5QGL7byi32Y0ld8mHP2KFbXT2aga0f3S5rl-ikFkRxpaSxk0coE=-w150-h150-c
https://lh6.googleusercontent.com/proxy/XgDFopqdfCYmrzYi5NKRDYZYZgmJ2fyAn-9eN9QnXgmBezTviTAYV4ct07peVeZMerMND3ZwgZ-lK8Uv7B6FivV6LXqAJN4E7OVvtKYToSriuCRK4QOTuf6oFXG0KTetG-QJCoHZT77mWJtCGb0jG9tch59MJ0aWWZ1NA5X7wF4aMtoLSHkvAK2cuspI85CpPMj2ayu6wiG-0GT8fcAwRsVW64773g=-w150-h150-c
https://lh6.googleusercontent.com/proxy/WTq4Z72Acy7ykLcNmv9b_B2IQerfE4M7V00dxJ1o65IBz4OPyDzKkDBrVLAvqKdSjOHuTsHwTw5_UBINqKU3tFIOeEjCdsOs3yLkqG52YI-NGYvtw0EUohgu6Ps=-w150-h150-c
https://lh6.googleusercontent.com/proxy/uyiP15MOcfSPSHn6FU_LMK08w-0WiaDKQwC0e5rC67ZmdEqYqDYQDjHCkkH0UB0vxLRNpUw0jyz_YCvZ713hPuAeZM4xk7ZItIzNnkXRv_H-n8196YojFvVHZjbRYNZguxHtN7uAT1hxNvrRlRL-pdG9eiUs58rx_w=-w150-h150-c
https://lh4.googleusercontent.com/proxy/MBgkZaPJYX173801aVCotrRKb5pTCO3orWgu0cgsCuglj0bAQW7Za7HhaQUVk2NIUxg8MQz0qiizFGBTSZXdcUwpsmTPpz2rXYuZpqxgSAsxjZH4RUZW9P74EuM-_KzJQ7fKZx7sVK26kLxXr206i6DWH8LCCFa9utvSWevAS2OlYSYc17a09Z6Af5NJ7FoIJ6jxh1wnsuZhfwebq_4zQGDg4AF9XVrKayVrYExcBtx-kYqgjAqTiswm7YoO1yJGBUNkXh1aXC76C50WEOiYemdoXeygD1KIsRpExccCQZZ_NDjIgRMjBvPAGy-1Ue1xwCiXvgFu1P7AtZ2g0XA=-w150-h150-c
https://lh6.googleusercontent.com/proxy/9TiiPwVKm7hFE4kzBEeQ2nrwR8h3hjJ1KLMw6G5s-3_FzO0QorKfKYkubFvF-YDgMYyujUloeApsM00xuBWgQYJE4vRrcdXFoAik032DyRykwAYl7e87Qjqb2wnNMUpfmX1PTZo_OK6VC69sGQY9ISWevaI09tKI6w=-w150-h150-c
https://lh4.googleusercontent.com/proxy/bePdkudsqFAyihVJPg94KH4SKhVTwB0BSFiXEsCdQEZubli_o9RtbEctWtw1X5CC_x9JqM9vBPhWMyP29eBmkrCzi04osGEwiTOoaeLI3WhPl49w0UKeNvOONgkK3ZbPhJ4RFutptw71nhLoiWX2uAUDChy_zgxYmg=-w150-h150-c
https://lh5.googleusercontent.com/proxy/GgkEfaSJZU_ZrtKUpU3aqKBS-u1fUkz3wDJH7m3iPlFduw_C0yfprGaOGubYqxBdILL69inogeniN3zM83hh2EaBGS5wNJ8PfmSe1bUOy605NxMR19SPSgeLu0hGlrc_d16v-V1OtwxDt2SVDM382UQ=-w150-h150-c
https://lh3.googleusercontent.com/proxy/C04R8mKirMGoXC7SvbOwbMAh2BpjAUcqRhyFEoZhIg2bl55t5jgF6zLwXvAAe4O95ETW1fp1sIQSGgzCoxlFBp51LCEzyfvDiKkxt0LpYzHmNTeIxmGTlmBkRv4wRNGquW0ZBp1AWnjoqaGosgMWv0kQI6QTkgFTEI5tuhrLppr_0Xcfy4JNSqo8bSVxa_fb27Iih5Evf1RUSS6Umnc6wW3cHip0icT7QmfdebQs3LUvSUqHaaeDikc60NOQdZRX8tUcODic84RoOn41vM8NvBrZZuQgImC8GTPavaMTUIsEOK4QxSNUdxKduRcPpa0p=-w150-h150-c
https://lh4.googleusercontent.com/proxy/qpUSiYScbVAjAv63NKloqPadlLXD7xWo0eocfLMerlUozukyVTS4QWZYcJBPmkHuxJZCh85Zh1mEepVEeZH3JSMxQRrcE-4Apawmnw=-w150-h150-c
https://lh6.googleusercontent.com/proxy/CNvMvcbMHHckCXbyFXkRZnnuPr17TEzvspLGwIobu15dDsrlHt-3QKzi7kcHKvTpJZlCr2l-HhWOPBfJJzPRrd2gn734awWdE5jXRcqrnfly4bwnIPokO68_luWur73lg-k=-w150-h150-c
https://lh4.googleusercontent.com/proxy/eDks_caYi82LNyG2L2AMQENYCuL7LfaH5rhL-qT6QiVnb5r142EFLTe4u61mZf-1xE2UkJB9GfcUy4x5IfNOU-JCd78FMn--f1CldoEY9y7ouU5cdZ8=-w150-h150-c
https://lh6.googleusercontent.com/proxy/WsWb8Woo-ogEIuDkvaBpsxrizSDUwM_k6h9w1ma-d_i4f3c9Bpefe6llemcMlZNODP5hx_raBrZ6dlclfDXJpirHGgVuTFp3W_mCdrGWO1LCsQf6Nz3iyjgJIbFFv12K3rC9sy2sfV3kgpQRURxi50MwLLG4lUcDx8LIiHWk5bG-VR9IBpygAMPtL5LJoRN8fkg9Vh7RA-J8kkbDm8-xirGXhkYheENaly7yH3qpIo_3aBYrHzS1GsCULOfpjdEuw2OISw=-w150-h150-c