Getting item inside an XML tag and call to children() on null error

Question

I am working with the Amazon API and have noticed that there is a problem when the item does not exist in the XML I am searching through. The XML that I get in response looks like this:

<GetMatchingProductForIdResult status="Success" IdType="UPC" Id="082686052344">
  <Products>
    <Product>
      <Identifiers>
         <MarketplaceASIN>
            <MarketplaceId>ATVPDKIKX0DER</MarketplaceId>
            <ASIN>B000IDC1WO</ASIN>
         </MarketplaceASIN>
      </Identifiers>
      <AttributeSets>
          <ns2:ItemAttributes xml:lang="en-US" xmlns:ns2="http://mws.amazonservices.com/schema/Products/2011-10-01/default.xsd">
          <ns2:Binding>Toy</ns2:Binding>
          <ns2:Brand>Rubie's</ns2:Brand>
          <ns2:Color>Black</ns2:Color>
          <ns2:Department>unisex-child</ns2:Department>
          <ns2:Feature>Rubie's Costume Children's Zorro Hat and Eye Mask Set</ns2:Feature>
          <ns2:Feature>Child'S costume accessory</ns2:Feature>
          <ns2:Feature>Black eye mask</ns2:Feature>
          <ns2:ItemDimensions>
               <ns2:Height Units="inches">8.00</ns2:Height>
               <ns2:Length Units="inches">14.00</ns2:Length>
               <ns2:Width Units="inches">8.00</ns2:Width>
          </ns2:ItemDimensions>
          <ns2:Label>Rubies - Domestic</ns2:Label>
          <ns2:Languages>
              <ns2:Language>
                  <ns2:Name>english</ns2:Name>
                  <ns2:Type>Unknown</ns2:Type>
              </ns2:Language>
          </ns2:Languages>
          <ns2:ListPrice>
               <ns2:Amount>16.99</ns2:Amount>
               <ns2:CurrencyCode>USD</ns2:CurrencyCode>
          </ns2:ListPrice>
          <ns2:Manufacturer>Rubies - Domestic</ns2:Manufacturer>
          <ns2:ManufacturerMaximumAge Units="months">180.0</ns2:ManufacturerMaximumAge>
          <ns2:ManufacturerMinimumAge Units="months">48.0</ns2:ManufacturerMinimumAge>
          <ns2:Model>F5234_NS</ns2:Model>
          <ns2:PackageDimensions>
              <ns2:Height Units="inches">0.90</ns2:Height>
              <ns2:Length Units="inches">14.50</ns2:Length>
              <ns2:Width Units="inches">13.20</ns2:Width>
              <ns2:Weight Units="pounds">0.20</ns2:Weight>
          </ns2:PackageDimensions>
          <ns2:PackageQuantity>1</ns2:PackageQuantity>
          <ns2:PartNumber>F5234_NS</ns2:PartNumber>
          <ns2:ProductGroup>Toy</ns2:ProductGroup>
          <ns2:ProductTypeName>TOYS_AND_GAMES</ns2:ProductTypeName>
          <ns2:Publisher>Rubies - Domestic</ns2:Publisher>
          <ns2:SmallImage>
               <ns2:URL>http://ecx.images-amazon.com/images/I/51ZRwleH85L._SL75_.jpg</ns2:URL>
               <ns2:Height Units="pixels">75</ns2:Height>
               <ns2:Width Units="pixels">57</ns2:Width>
          </ns2:SmallImage>
          <ns2:Studio>Rubies - Domestic</ns2:Studio>
          <ns2:Title>Rubie's Costume Children's Zorro Hat and Eye Mask Set</ns2:Title>
          <ns2:Warranty>No Warranty</ns2:Warranty>
          </ns2:ItemAttributes>
       </AttributeSets>
    <Relationships/>
    <SalesRankings>
      <SalesRank>
        <ProductCategoryId>toy_display_on_website</ProductCategoryId>
        <Rank>481818</Rank>
      </SalesRank>
      <SalesRank>
       <ProductCategoryId>2229578011</ProductCategoryId>
       <Rank>469</Rank>
       </SalesRank>
       </SalesRankings>
   </Product>
  </Products>
</GetMatchingProductForIdResult>

If there is a client error, then I receive this:

<GetMatchingProductForIdResult Id="082686035408" IdType="UPC" status="ClientError">
   <Error>
     <Type>Sender</Type>
     <Code>InvalidParameterValue</Code>
     <Message>Invalid UPC identifier 082686035408 for marketplace ATVPDKIKX0DER</Message>
   </Error>
</GetMatchingProductForIdResult>

I am totally unaware of how I would deal with this since I am doing mass scans at a time. So far for PHP code, I have this:

$xmlFiles = glob("xml/*xml");
//Checking if multiple xml files exist. 
if(is_array($xmlFiles)){
   foreach($xmlFiles as $xmlFile){
     $xml = simplexml_load_file($xmlFile);
     //problem 'Status' is = 'Client Error'
     foreach($xml->GetMatchingProductForIdResult as $items) { 
        print_r($items);
        //Getting UPC
        if(isset($items['Id'])){ 
            $id = $items['Id']; 
        }else{
            $id = 'No Id Found';
        }
        //Getting ASIN From XML
        if(isset($items->Products->Product->Identifiers->MarketplaceASIN->ASIN)){ 
            $asin = $items->Products->Product->Identifiers->MarketplaceASIN->ASIN;
        }else{
            $asin = 'No Asin Found';
        }
        if(isset($items->Products->Product->SalesRankings->SalesRank[0]->Rank)){ 
            $salesRank = $items->Products->Product->SalesRankings->SalesRank[0]->Rank;
        }else{
            $salesRank = 'Sales Rank Not Found';
        }
        if(($items['Status']) != 'ClientError'){
            if(isset($items->Products->Product->AttributeSets->children('ns2', true)->ItemAttributes->ListPrice->Amount)) { 
                $amount = $items->Products->Product->AttributeSets->children('ns2', true)->ItemAttributes->ListPrice->Amount;
            }else{
            $amount = '0.00';
            }
            if(isset($items->Products->Product->AttributeSets->children('ns2', true)->ItemAttributes->PackageDimensions->Height) !== False){
                $height =$items->Products->Product->AttributeSets->children('ns2', true)->ItemAttributes->PackageDimensions->Height;            
            } else {
                $height = '';
            }
            if(isset($items->Products->Product->AttributeSets->children('ns2', true)->ItemAttributes->PackageDimensions->Length) !== False){
                $length = $items->Products->Product->AttributeSets->children('ns2', true)->ItemAttributes->PackageDimensions->Length;
            } else {
                $length = '';
            }       
            if(isset($items->Products->Product->AttributeSets->children('ns2', true)->ItemAttributes->PackageDimensions->Width)){
                $width = $items->Products->Product->AttributeSets->children('ns2', true)->ItemAttributes->PackageDimensions->Width;
            } else {
                $width = '';
            }

            if(($length+$width+$height) < 27.75){
                $oversize = '';
            } elseif (($length+$width+$height) > 27.75 && ($length+$width+$height) < 40) {
                $oversize = 'Small Oversize';
            } elseif(($length+$width+$height) > 40){
            $oversize = 'Large oversize';
            } 
            $sqlImport = "INSERT INTO " . $fileName . "(id, asin, salesRank, Amount, Oversize)
            VALUES('$id', '$asin', '$salesRank', '$amount', '$oversize')";
             if ($sqlConnection->query($sqlImport) === TRUE) {
              echo "New record created successfully";
             } else {
              echo "Error: " . $sqlImport . "<br>" .    $sqlConnection->error;
        }
    } else {
        die('Sorry for an unexpected error');
    }
}

} } I am not sure how I would implement your answer into the following code. I am sorting through multiple XML files that have 5 of each tag in it.

I have this error when there is also a client error:

Fatal error: Call to a member function children() on null in J:\XAMPP\htdocs\Phillip\src\MarketplaceWebServiceProducts\Samples\csv_prep.php on line 110

Line 110 is:

if(isset($items->Products->Product->AttributeSets->children('ns2', true)->ItemAttributes->ListPrice->Amount) !== False) { 
     $amount = $items->Products->Product->AttributeSets->children('ns2', true)->ItemAttributes->ListPrice->Amount;
}else{
     $amount = '0.00';
    }

The current file that I am testing on does have 80 XML files that it goes through.If anyone has anyway to help me out, I would greatly appreciate it. Thanks in advance.

Not enough information for us to be any help.Please read [How to ask a good question](http://stackoverflow.com/help/how-to-ask) And [the perfect question](http://codeblog.jonskeet.uk/2010/08/29/writing-the-perfect-question/) — RiggsFolly, Jan 16 '16 at 16:05
Parse the xml with DOMDocument and find what you need using XPath — Professor Abronsius, Jan 16 '16 at 16:33
@RamRaider how would I go about doing that? Can you answer with a way that I could do that? — Teddy Codes, Jan 17 '16 at 04:17
@RiggsFolly I added more information to the question. Thanks. — Teddy Codes, Jan 17 '16 at 04:18

Professor Abronsius · Answer 1 · 2016-01-17T16:34:19.683

Rather than using simplexml the following uses the standard DOMDocument and approach to access nodes in the xml document. Once you have found the root node you can test fr the first child which is different if there is an error ( Products if ok, Error if not ok ) - from that point you can fork the processing with if / else

I'm sure that you will be able to convert this or adopt the approach using simplexml - never used it so I don't know what is involved.

Given the drastic change in the question's content from when I posted initial comment to the code shown above I can see no need to use an XPath query - hence this approach.

$dom = new DOMDocument();
$dom->loadXML( $strxml );
$dom->preserveWhiteSpace = true;

$root=$dom->getElementsByTagName('GetMatchingProductForIdResult')->item(0);
$children=$root->childNodes;
$child=$children->item(1);

if( $child->tagName=='Error' ){
    echo 'oh no, we broke the interwebs';
} else {
    echo 'all good, proceed to process xml';
}

$dom = $root = null;

full example:

$strxml='<GetMatchingProductForIdResult status="Success" IdType="UPC" Id="082686052344">
          <Products>
            <Product>
              <Identifiers>
                 <MarketplaceASIN>
                    <MarketplaceId>ATVPDKIKX0DER</MarketplaceId>
                    <ASIN>B000IDC1WO</ASIN>
                 </MarketplaceASIN>
              </Identifiers>
              <AttributeSets>
                  <ns2:ItemAttributes xml:lang="en-US" xmlns:ns2="http://mws.amazonservices.com/schema/Products/2011-10-01/default.xsd">
                  <ns2:Binding>Toy</ns2:Binding>
                  <ns2:Brand>Rubie\'s</ns2:Brand>
                  <ns2:Color>Black</ns2:Color>
                  <ns2:Department>unisex-child</ns2:Department>
                  <ns2:Feature>Rubie\'s Costume Children\'s Zorro Hat and Eye Mask Set</ns2:Feature>
                  <ns2:Feature>Child\'S costume accessory</ns2:Feature>
                  <ns2:Feature>Black eye mask</ns2:Feature>
                  <ns2:ItemDimensions>
                       <ns2:Height Units="inches">8.00</ns2:Height>
                       <ns2:Length Units="inches">14.00</ns2:Length>
                       <ns2:Width Units="inches">8.00</ns2:Width>
                  </ns2:ItemDimensions>
                  <ns2:Label>Rubies - Domestic</ns2:Label>
                  <ns2:Languages>
                      <ns2:Language>
                          <ns2:Name>english</ns2:Name>
                          <ns2:Type>Unknown</ns2:Type>
                      </ns2:Language>
                  </ns2:Languages>
                  <ns2:ListPrice>
                       <ns2:Amount>16.99</ns2:Amount>
                       <ns2:CurrencyCode>USD</ns2:CurrencyCode>
                  </ns2:ListPrice>
                  <ns2:Manufacturer>Rubies - Domestic</ns2:Manufacturer>
                  <ns2:ManufacturerMaximumAge Units="months">180.0</ns2:ManufacturerMaximumAge>
                  <ns2:ManufacturerMinimumAge Units="months">48.0</ns2:ManufacturerMinimumAge>
                  <ns2:Model>F5234_NS</ns2:Model>
                  <ns2:PackageDimensions>
                      <ns2:Height Units="inches">0.90</ns2:Height>
                      <ns2:Length Units="inches">14.50</ns2:Length>
                      <ns2:Width Units="inches">13.20</ns2:Width>
                      <ns2:Weight Units="pounds">0.20</ns2:Weight>
                  </ns2:PackageDimensions>
                  <ns2:PackageQuantity>1</ns2:PackageQuantity>
                  <ns2:PartNumber>F5234_NS</ns2:PartNumber>
                  <ns2:ProductGroup>Toy</ns2:ProductGroup>
                  <ns2:ProductTypeName>TOYS_AND_GAMES</ns2:ProductTypeName>
                  <ns2:Publisher>Rubies - Domestic</ns2:Publisher>
                  <ns2:SmallImage>
                       <ns2:URL>http://ecx.images-amazon.com/images/I/51ZRwleH85L._SL75_.jpg</ns2:URL>
                       <ns2:Height Units="pixels">75</ns2:Height>
                       <ns2:Width Units="pixels">57</ns2:Width>
                  </ns2:SmallImage>
                  <ns2:Studio>Rubies - Domestic</ns2:Studio>
                  <ns2:Title>Rubie\'s Costume Children\'s Zorro Hat and Eye Mask Set</ns2:Title>
                  <ns2:Warranty>No Warranty</ns2:Warranty>
                  </ns2:ItemAttributes>
               </AttributeSets>
            <Relationships/>
            <SalesRankings>
              <SalesRank>
                <ProductCategoryId>toy_display_on_website</ProductCategoryId>
                <Rank>481818</Rank>
              </SalesRank>
              <SalesRank>
               <ProductCategoryId>2229578011</ProductCategoryId>
               <Rank>469</Rank>
               </SalesRank>
               </SalesRankings>
           </Product>
          </Products>
        </GetMatchingProductForIdResult>';


$dom = new DOMDocument();
$dom->loadXML( $strxml );
$dom->preserveWhiteSpace = true;

$root=$dom->getElementsByTagName('GetMatchingProductForIdResult')->item(0);
$children=$root->childNodes;
$child=$children->item(1);

if( $child->tagName=='Error' ){

    echo 'oh no, we broke the interwebs';

} else {

    if( !defined('BR') ) define('BR','<br />');

    /* create an XPath object */
    $xp=new DOMXPath( $dom );

    /* define prefix and namespace uri */
    $namespace = 'http://mws.amazonservices.com/schema/Products/2011-10-01/default.xsd';
    $prefix = 'ns2';

    /* associate the namespace with the dom content */
    $xp->registerNamespace( $prefix, $namespace );



    /* target particular node */
    $nodename='Manufacturer';

    /* ex#1 run the xpath query */
    $col=$xp->query( "//{$prefix}:{$nodename}" );
    if( $col ) echo $col->item(0)->nodeValue;   


    /* ex#2 */
    $nodename='Title';
    $col=$xp->query( "//{$prefix}:{$nodename}" );
    if( $col ) echo $col->item(0)->nodeValue;

    /* Alternatively, get childnodes of particular node that have namespaces */
    $col=$dom->getElementsByTagNameNS( $namespace, 'ItemAttributes')->item(0);
    if( $col ){
        foreach( $col->childNodes as $child ) if( $child->nodeType==XML_ELEMENT_NODE ) echo 'tag:'.$child->tagName.' -> value:'.$child->nodeValue . BR; 
    }
}
$dom = $root = $xp = $col = $namespace = $prefix = $nodename = null;

update

$col=$xp->query( "//MarketplaceASIN" );/* no namespace */
$asin=$col ? $col->item(0)->nodeValue : false;

$col=$xp->query('//SalesRank/Rank');/* no namespace */
$rank=$col ? $col->item(0)->nodeValue : false;

$col=$xp->query("//{$prefix}:ListPrice/{$prefix}:Amount");
$amount=$col ? $col->item(0)->nodeValue : false;

$col=$xp->query("//{$prefix}:PackageDimensions/{$prefix}:Length");
$length=$col ? $col->item(0)->nodeValue : false;

$col=$xp->query("//{$prefix}:PackageDimensions/{$prefix}:Height");
$height=$col ? $col->item(0)->nodeValue : false;

$col=$xp->query("//{$prefix}:PackageDimensions/{$prefix}:Width");
$width=$col ? $col->item(0)->nodeValue : false;


echo $asin.BR.$rank.BR.$amount.BR.$length.BR.$height.BR.$width.BR.BR.$root->tagName.BR.$root->getAttribute('Id');

How would I go about getting the name space values since there is a : in between the wording? — Teddy Codes, Jan 17 '16 at 12:25
Of relevance to your request would be this http://stackoverflow.com/questions/595946/parse-xml-with-namespace-using-simplexml — Professor Abronsius, Jan 17 '16 at 14:01
It it possible for you to give a example using dom? I am very new to dom. I only know somewhat simplexml. I am very new to php — Teddy Codes, Jan 17 '16 at 14:06
updated question. I am having a hard time figuring out where I could possibly implement that code that you gave. Thanks. — Teddy Codes, Jan 17 '16 at 15:22
I appreciate It. I will get back to you if a problem occurs. I will check it out now. — Teddy Codes, Jan 17 '16 at 15:50
Will it still loop through the xml if I put it in the `second` for each loop? — Teddy Codes, Jan 17 '16 at 15:51

Getting item inside an XML tag and call to children() on null error

1 Answers1

full example:

update

Linked