生成 XML

【问题标题】：Generate an XML生成 XML
【发布时间】：2015-01-31 00:27:36
【问题描述】：

我制作了一个脚本，它可以根据我的 Mysql 数据库中的一些表生成 XML。 该脚本在 PHP 中运行。

public function getRawMaterials($apiKey, $format = 'json') {
    if($this::checkApiKey($apiKey)) {
        if(!Cache::has($apiKey . '_rawMaterialData')) {
            $companyID = DB::table('apiKeys')
                ->select('companyID')
                ->where('apiKey', $apiKey)
                ->pluck('companyID');

            $rawMaterials = DB::table('rawMaterials')
                ->join('companySupplier', 'companySupplier.supplier', '=', 'rawMaterials.supplierID')
                ->where('companySupplier.company', $companyID)
                ->take(3)
                ->get();

            $nutritions = DB::table('nevoExpl')->select('nutrientcode', 'nederlandse_nutrientnaam', 'meeteenheid_nutrient')->get();
            $allergens = DB::table('allergens')->get();
            $dangers = DB::table('dangers')->get();

            $data = (array)$rawMaterials;

            for($i = 0; $i < sizeof($data); $i++) {

                $data[$i] = (array)$data[$i];

                // Initialize these variables
                $data[$i]['ingredients'] = array();
                $data[$i]['nutritions'] = array();
                $data[$i]['allergens'] = array();
                //$data[$i]['dangers'] = array();

                $ingredients = DB::table('ingredients')
                    ->select('ingredients.*', 'rawMaterialIngredients.weight')
                    ->join('rawMaterialIngredients', 'rawMaterialIngredients.ingredientID', '=', 'ingredients.ingredientID')
                    ->where('rawMaterialIngredients.rawMaterialID', $data[$i]['rawMaterialID'])
                    ->get();

                $data[$i]['ingredients'] = (array)$ingredients;

                for($j = 0; $j < sizeof($data[$i]['ingredients']); $j++) {

                    $data[$i]['ingredients'][$j] = (array)$ingredients[$j];

                    // Check what allergens are in the products
                    foreach($allergens as $allergen) {
                        if(array_key_exists($allergen->allergen, $data[$i])) {
                            if(!array_key_exists($allergen->allergen, $data[$i]['allergens']) && $data[$i][$allergen->allergen] == "M") {
                                $data[$i]['allergens'][$allergen->id] = array(
                                    'allergenID'    => $allergen->id,
                                    'allergenName'  => $allergen->allergen,
                                    'allergenValue' => 'M'
                                );
                            }

                            unset($data[$i][$allergen->allergen]);
                        }

                        if(array_key_exists($allergen->allergen, $data[$i]['ingredients'][$j])) {
                            if(!array_key_exists($allergen->allergen, $data[$i]['allergens']) && $data[$i]['ingredients'][$j][$allergen->allergen] == "M") {
                                $data[$i]['allergens'][$allergen->id] = array(
                                    'allergenID'    => $allergen->id,
                                    'allergenName'  => $allergen->allergen,
                                    'allergenValue' => 'M'
                                );
                            }

                            unset($data[$i]['ingredients'][$j][$allergen->allergen]);
                        }
                    }

                    // foreach($dangers as $danger) {
                        // if(array_key_exists($danger->danger, $data[$i]['ingredients'][$j])) {
                            // if(array_key_exists($danger->danger, $data[$i]['dangers'])) {
                                // $data[$i]['dangers'][$danger->danger] = "M";
                            // }

                            // unset($data[$i]['ingredients'][$j][$danger->danger]);
                        // }
                    // }
                }

                foreach($nutritions as $nutrition) {
                    if(!array_key_exists($nutrition->nutrientcode, $data[$i]['nutritions'])) {
                        $data[$i]['nutritions'][] = array(
                            'nutritionCode'     => $nutrition->nutrientcode,
                            'nutritionName'     => $nutrition->nederlandse_nutrientnaam,
                            'nutritionMeasure'  => $nutrition->meeteenheid_nutrient,
                            'nutritionValue'    => $data[$i][$nutrition->nutrientcode]
                        );
                    }

                    // Don't need this anymore, so let's get rid of it!
                    unset($data[$i][$nutrition->nutrientcode]);
                }
            }

            $data['Generated_on'] = date('d-m-Y G:i:s', time());

            Cache::put($apiKey . '_rawMaterialData', $data, 720);

        }
        else {
            $data = Cache::get($apiKey . '_rawMaterialData');
        }
    }
    else {
        $data['error'] = 'Dit is geen geldige API code.';
    }

    return $this::format($data, $format);
}

使用这个脚本的问题是它在处理大量数据时会耗尽内存。 然而，我们需要处理这么多数据，因为我们想要制作一个可供客户使用的 xml。

目前我们将此脚本作为 API 运行，但我们愿意接受其他建议（甚至是与 PHP 无关的建议） 我们只是想要一种将我们的产品（到 API、FTP 或其他）导出到 XML（和 JSON）文件的方法，以便我们的客户可以使用它。我们也希望它是轻量级的。我们还希望它具有以下级别：

<xml>
    <item>
        <rawMaterialID>567</rawMaterialID>
        <rawMaterialName>Gehakt 60 40  HOH</rawMaterialName>
        <rawMaterialSpecDate>2014-10-19 16:17:14</rawMaterialSpecDate>
        <rawMaterialSpecSource>koetsier vleeswaren bv</rawMaterialSpecSource>
        <supplierID>28</supplierID>
        <supplierDescription>gehakt hoh</supplierDescription>
        <articleNumber>60250</articleNumber>
        <supplierArticleNumber>2002733</supplierArticleNumber>
        <barCode>0</barCode>
        <originCountry>1</originCountry>
        <productionCountry>1</productionCountry>
        <id>1</id>
        <company>15</company>
        <supplier>28</supplier>
        <ingredients>
            <ingredient>
                <ingredientID>226</ingredientID>
                <ingredientName>varkensvlees</ingredientName>
                <ingredientNameIMIS>varkensvlees</ingredientNameIMIS>
                <enumber/>
                <enumberAddition/>
                <general_comments/>
                <further_info/>
                <albaList>Varkensvlees</albaList>
                <adi/>
                <aeromonas>Z</aeromonas>
                <baccereus>Z</baccereus>
                <campylobact>Z</campylobact>
                <clostbot>Z</clostbot>
                <clost_Perf>Z</clost_Perf>
                <e_coli>Z</e_coli>
                <e_coli_O157H7>Z</e_coli_O157H7>
                <listeria>Z</listeria>
                <salmonella>Z</salmonella>
                <shigella>Z</shigella>
                <staph_Aur>Z</staph_Aur>
                <staph_coag>Z</staph_coag>
                <yersinia>Z</yersinia>
                <vibrio_col>Z</vibrio_col>
                <vibrio_para>Z</vibrio_para>
                <vibrio_vuln>Z</vibrio_vuln>
                <mycobacteria>Z</mycobacteria>
                <brucella>Z</brucella>
                <aflatoxin>Z</aflatoxin>
                <patuline>Z</patuline>
                <echratoxin>Z</echratoxin>
                <fusarium>Z</fusarium>
                <ergot>Z</ergot>
                <fumonisin>Z</fumonisin>
                <rubratoxin>Z</rubratoxin>
                <zearalenone>Z</zearalenone>
                <hepatitis>Z</hepatitis>
                <viral_gastroenteritis>Z</viral_gastroenteritis>
                <polio>Z</polio>
                <rickets>Z</rickets>
                <prions>Z</prions>
                <moulds_yeast>Z</moulds_yeast>
                <anisakis_marina>Z</anisakis_marina>
                <cryptosporidium_parvum>Z</cryptosporidium_parvum>
                <echinococcus_granulosis>Z</echinococcus_granulosis>
                <entamoeba_histolytica>Z</entamoeba_histolytica>
                <giardia_lamblia>Z</giardia_lamblia>
                <fasciola_hepatica>Z</fasciola_hepatica>
                <clonorchis_sinensis>Z</clonorchis_sinensis>
                <taenia_saginata>Z</taenia_saginata>
                <taenia_solium>Z</taenia_solium>
                <toxoplasma_gondii>Z</toxoplasma_gondii>
                <trichinella_spiralis>Z</trichinella_spiralis>
                <meelmijt_Tyroglyphus_farinae_L>Z</meelmijt_Tyroglyphus_farinae_L>
                <flies>Z</flies>
                <ants>Z</ants>
                <mites>Z</mites>
                <beetles>Z</beetles>
                <cockroaches>Z</cockroaches>
                <moths>Z</moths>
                <rodents>Z</rodents>
                <weevils>Z</weevils>
                <bone_fragments>Z</bone_fragments>
                <stones>Z</stones>
                <insect_fragments>Z</insect_fragments>
                <choke>Z</choke>
                <metal_fragments>Z</metal_fragments>
                <glass>Z</glass>
                <createdBy/>
                <dateCreated>2014-07-02 14:38:22</dateCreated>
                <changedBy/>
                <dateChanged/>
                <weight>600</weight>
            </ingredient>
            <ingredient>
                <ingredientID>200</ingredientID>
                <ingredientName>rundvlees</ingredientName>
                <ingredientNameIMIS>rundvlees</ingredientNameIMIS>
                <enumber/>
                <enumberAddition/>
                <general_comments/>
                <further_info/>
                <albaList>Rundvlees</albaList>
                <adi/>
                <aeromonas>Z</aeromonas>
                <baccereus>Z</baccereus>
                <campylobact>Z</campylobact>
                <clostbot>Z</clostbot>
                <clost_Perf>Z</clost_Perf>
                <e_coli>Z</e_coli>
                <e_coli_O157H7>Z</e_coli_O157H7>
                <listeria>Z</listeria>
                <salmonella>Z</salmonella>
                <shigella>Z</shigella>
                <staph_Aur>Z</staph_Aur>
                <staph_coag>Z</staph_coag>
                <yersinia>Z</yersinia>
                <vibrio_col>Z</vibrio_col>
                <vibrio_para>Z</vibrio_para>
                <vibrio_vuln>Z</vibrio_vuln>
                <mycobacteria>Z</mycobacteria>
                <brucella>Z</brucella>
                <aflatoxin>Z</aflatoxin>
                <patuline>Z</patuline>
                <echratoxin>Z</echratoxin>
                <fusarium>Z</fusarium>
                <ergot>Z</ergot>
                <fumonisin>Z</fumonisin>
                <rubratoxin>Z</rubratoxin>
                <zearalenone>Z</zearalenone>
                <hepatitis>Z</hepatitis>
                <viral_gastroenteritis>Z</viral_gastroenteritis>
                <polio>Z</polio>
                <rickets>Z</rickets>
                <prions>Z</prions>
                <moulds_yeast>Z</moulds_yeast>
                <anisakis_marina>Z</anisakis_marina>
                <cryptosporidium_parvum>Z</cryptosporidium_parvum>
                <echinococcus_granulosis>Z</echinococcus_granulosis>
                <entamoeba_histolytica>Z</entamoeba_histolytica>
                <giardia_lamblia>Z</giardia_lamblia>
                <fasciola_hepatica>Z</fasciola_hepatica>
                <clonorchis_sinensis>Z</clonorchis_sinensis>
                <taenia_saginata>Z</taenia_saginata>
                <taenia_solium>Z</taenia_solium>
                <toxoplasma_gondii>Z</toxoplasma_gondii>
                <trichinella_spiralis>Z</trichinella_spiralis>
                <meelmijt_Tyroglyphus_farinae_L>Z</meelmijt_Tyroglyphus_farinae_L>
                <flies>Z</flies>
                <ants>Z</ants>
                <mites>Z</mites>
                <beetles>Z</beetles>
                <cockroaches>Z</cockroaches>
                <moths>Z</moths>
                <rodents>Z</rodents>
                <weevils>Z</weevils>
                <bone_fragments>Z</bone_fragments>
                <stones>Z</stones>
                <insect_fragments>Z</insect_fragments>
                <choke>Z</choke>
                <metal_fragments>Z</metal_fragments>
                <glass>Z</glass>
                <createdBy/>
                <dateCreated>2014-07-02 14:38:22</dateCreated>
                <changedBy/>
                <dateChanged/>
                <weight>400</weight>
            </ingredient>
        </ingredients>
        <nutritions>
            <nutrition>
                <nutritionCode>n_01001</nutritionCode>
                <nutritionName>Energie</nutritionName>
                <nutritionMeasure>kcal</nutritionMeasure>
                <nutritionValue>233</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_01002</nutritionCode>
                <nutritionName>Energie</nutritionName>
                <nutritionMeasure>kJ</nutritionMeasure>
                <nutritionValue>969</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_02001</nutritionCode>
                <nutritionName>Stikstof totaal</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>3.1</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_02002</nutritionCode>
                <nutritionName>Eiwit totaal</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>19.2</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_02003</nutritionCode>
                <nutritionName>Eiwit plantaardig</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_02004</nutritionCode>
                <nutritionName>Eiwit dierlijk</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>19.2</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_03001</nutritionCode>
                <nutritionName>Vet totaal</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>17.2</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_03002</nutritionCode>
                <nutritionName>Som van de vetzuren</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>16.2</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_03004</nutritionCode>
                <nutritionName>Vetzuren totaal verzadigd</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>6.9</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_03006</nutritionCode>
                <nutritionName>Vetzuren enkelv onverz cis</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>7.5</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_03008</nutritionCode>
                <nutritionName>Vetzuren meerv onverz</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>1.3</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_03009</nutritionCode>
                <nutritionName>Linolzuur (C18:2(n-6)cis)</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>1.1</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_03136</nutritionCode>
                <nutritionName>Vetzuren totaal trans</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_04001</nutritionCode>
                <nutritionName>Cholesterol</nutritionName>
                <nutritionMeasure>mg</nutritionMeasure>
                <nutritionValue>28.8</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_05001</nutritionCode>
                <nutritionName>Koolhydraten totaal</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>0.3</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_05002</nutritionCode>
                <nutritionName>Suiker Totaal</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>0.3</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_05003</nutritionCode>
                <nutritionName>Glucose</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_05005</nutritionCode>
                <nutritionName>Fructose</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_05006</nutritionCode>
                <nutritionName>Lactose</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_05008</nutritionCode>
                <nutritionName>Maltose</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_05009</nutritionCode>
                <nutritionName>Saccharose</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_05010</nutritionCode>
                <nutritionName>Polysacchariden totaal</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_05011</nutritionCode>
                <nutritionName>Polyolen totaal</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_05012</nutritionCode>
                <nutritionName>Lactitol</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_05013</nutritionCode>
                <nutritionName>Xylitol</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_05014</nutritionCode>
                <nutritionName>Sorbitol</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_05015</nutritionCode>
                <nutritionName>Isomalt</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_06001</nutritionCode>
                <nutritionName>Voedingsvezel totaal</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>0.3</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_07001</nutritionCode>
                <nutritionName>Water</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>63.7</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_08001</nutritionCode>
                <nutritionName>Alcohol totaal</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_09001</nutritionCode>
                <nutritionName>Calcium</nutritionName>
                <nutritionMeasure>mg</nutritionMeasure>
                <nutritionValue>9</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_09002</nutritionCode>
                <nutritionName>Fosfor</nutritionName>
                <nutritionMeasure>mg</nutritionMeasure>
                <nutritionValue>169</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_09003</nutritionCode>
                <nutritionName>IJzer totaal</nutritionName>
                <nutritionMeasure>mg</nutritionMeasure>
                <nutritionValue>1.3</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_09006</nutritionCode>
                <nutritionName>Natrium</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>0.177</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_09007</nutritionCode>
                <nutritionName>Kalium</nutritionName>
                <nutritionMeasure>mg</nutritionMeasure>
                <nutritionValue>303</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_09008</nutritionCode>
                <nutritionName>Magnesium</nutritionName>
                <nutritionMeasure>mg</nutritionMeasure>
                <nutritionValue>19</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_09009</nutritionCode>
                <nutritionName>Zink</nutritionName>
                <nutritionMeasure>mg</nutritionMeasure>
                <nutritionValue>3.22</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_10001</nutritionCode>
                <nutritionName>Selenium</nutritionName>
                <nutritionMeasure>ug</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_10002</nutritionCode>
                <nutritionName>Koper</nutritionName>
                <nutritionMeasure>mg</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_10003</nutritionCode>
                <nutritionName>Jodium</nutritionName>
                <nutritionMeasure>ug</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_11001</nutritionCode>
                <nutritionName>Retinol</nutritionName>
                <nutritionMeasure>ug</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_11002</nutritionCode>
                <nutritionName>Retinol equivalenten</nutritionName>
                <nutritionMeasure>ug</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_11003</nutritionCode>
                <nutritionName>Beta-caroteen</nutritionName>
                <nutritionMeasure>ug</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_11005</nutritionCode>
                <nutritionName>Vitamine B1</nutritionName>
                <nutritionMeasure>mg</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_11006</nutritionCode>
                <nutritionName>Vitamine B2</nutritionName>
                <nutritionMeasure>mg</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_11007</nutritionCode>
                <nutritionName>Vitamine B6 totaal</nutritionName>
                <nutritionMeasure>mg</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_11008</nutritionCode>
                <nutritionName>Vitamine B12</nutritionName>
                <nutritionMeasure>ug</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_11009</nutritionCode>
                <nutritionName>Vitamine D totaal</nutritionName>
                <nutritionMeasure>ug</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_11010</nutritionCode>
                <nutritionName>Vitamine E totaal</nutritionName>
                <nutritionMeasure>mg</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_11011</nutritionCode>
                <nutritionName>Vitamine C</nutritionName>
                <nutritionMeasure>mg</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_11013</nutritionCode>
                <nutritionName>Foliumzuur</nutritionName>
                <nutritionMeasure>ug</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_11014</nutritionCode>
                <nutritionName>Nicotinezuur</nutritionName>
                <nutritionMeasure>mg</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_11020</nutritionCode>
                <nutritionName>Alfa-caroteen</nutritionName>
                <nutritionMeasure>ug</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_11022</nutritionCode>
                <nutritionName>Zeaxanthine</nutritionName>
                <nutritionMeasure>ug</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_11024</nutritionCode>
                <nutritionName>Lycopeen</nutritionName>
                <nutritionMeasure>ug</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_11035</nutritionCode>
                <nutritionName>Vitamine K totaal</nutritionName>
                <nutritionMeasure>ug</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_11036</nutritionCode>
                <nutritionName>Vitamine K1</nutritionName>
                <nutritionMeasure>ug</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_11038</nutritionCode>
                <nutritionName>Vitamine K2</nutritionName>
                <nutritionMeasure>ug</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_11039</nutritionCode>
                <nutritionName>Zout</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_11040</nutritionCode>
                <nutritionName>Omega 3 vetzuren N-3</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
            <nutrition>
                <nutritionCode>n_11041</nutritionCode>
                <nutritionName>Omega 6 vetzuren N-6</nutritionName>
                <nutritionMeasure>g</nutritionMeasure>
                <nutritionValue>0</nutritionValue>
            </nutrition>
        </nutritions>
        <allergens>
            <allergen>
                <allergenID>14</allergenID>
                <allergenName>rundvlees</allergenName>
                <allergenValue>M</allergenValue>
            </allergen>
            <allergen>
                <allergenID>15</allergenID>
                <allergenName>varkensvlees</allergenName>
                <allergenValue>M</allergenValue>
            </allergen>
        </allergens>
    </item>
</xml>

我希望有人可以帮助我们。

【问题讨论】：

  • 如果我没看错，您正在构建一个海量数据结构，然后以特定格式输出。如果您有内存问题，解决此问题的正常方法是将其拆分为较小的结构并逐个输出。这类似于某些 XML 阅读器的工作方式（使用回调）。这将是一个不平凡的切换，但如果你想减少内存使用量，它最初似乎是唯一的选择。
  • 基本思想 - 分解你的结构并编写一些将输出单个实体的东西 - 在你的循环中调用它，随着你的进行丢弃数据结构。也就是说，您的数据库库可能会遇到问题，因为看起来您可以从那里一口气获得所有内容。您最好对每条返回的记录进行回调，或者在返回结果集时循环遍历结果集，而不是在将其全部从数据库中取出后进行循环。
  • 是的，我也一直在考虑让 centos 像每小时通过 cronjob 一次运行 50 条记录一样运行这个脚本。但是，难道没有像官方的方式来处理这种事情吗？
  • “官方”？你的意思是像 PHP 管理机构正式批准的那样？ ;-) 我知道你的意思，是的，我会说“官方”的做法是编写一些可以轻松分解并在使用资源时丢弃资源的东西。那可以是使用回调，也可以是-&gt;next 样式循环/迭代器
  • 你能写一个你的建议的小例子吗@Rob Baillie

标签： php xml json api centos


【解决方案1】：

什么时候抛出错误？数据量是多少？

如果在格式化操作过程中出现内存不足的错误，也许你可以将你的大 json 或 xml 拆分为多个文件，然后将它们连接起来。

但是在任何情况下你应该做的真正的事情是如果你的数据库包含 100 万条记录，那么你的输出页面最多可以输出 n 个实体，这并不奇怪你的 php 抱怨内存......

如果你不这样做，你的客户会遇到同样的问题，当他们试图解析你的数据时内存不足......

【讨论】：

  • 这取决于客户想要导出的数据，我会说大约 2000 条记录或更多。所以你是说我应该把工作分成多个文件，然后把它们连接起来？拆分多少实体比较合适？
  • 你能举个小例子吗？
  • 如果不为您编写整个代码，很难举个例子。但是为了避免内存问题，您可以在 SQL（分页数据）中使用 LIMIT N OFFSET X 来限制迭代的数据量，执行 n 次（n 代表“必要”:)）。然后您使用文件流逐行输出数据以限制程序的占用空间。 Personnaly 我会创建一个对象来保持最后打开的 xml 标记的状态以执行此部分。
  • 所以基本上写一个处理50条记录的函数，然后使用递归再次调用该函数为接下来的50条记录？
  • 你可以这样做，但是恕我直言，重要的部分是你输出 XML 的方式（实际上，这取决于内存问题发生的时间）。
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