Ricevere un documento Firestore durante l'uso di shard
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Ricevere un documento Firestore durante l'uso di shard
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Per la documentazione dettagliata che include questo esempio di codice, vedi quanto segue:
Esempio di codice
Salvo quando diversamente specificato, i contenuti di questa pagina sono concessi in base alla licenza Creative Commons Attribution 4.0, mentre gli esempi di codice sono concessi in base alla licenza Apache 2.0. Per ulteriori dettagli, consulta le norme del sito di Google Developers. Java è un marchio registrato di Oracle e/o delle sue consociate.
[[["Facile da capire","easyToUnderstand","thumb-up"],["Il problema è stato risolto","solvedMyProblem","thumb-up"],["Altra","otherUp","thumb-up"]],[["Difficile da capire","hardToUnderstand","thumb-down"],["Informazioni o codice di esempio errati","incorrectInformationOrSampleCode","thumb-down"],["Mancano le informazioni o gli esempi di cui ho bisogno","missingTheInformationSamplesINeed","thumb-down"],["Problema di traduzione","translationIssue","thumb-down"],["Altra","otherDown","thumb-down"]],[],[[["\u003cp\u003eThis document provides code samples in multiple languages (C#, Go, Node.js, PHP, Python, Ruby) for retrieving a total count from a Firestore document that uses sharding.\u003c/p\u003e\n"],["\u003cp\u003eThe core functionality involves iterating through a collection of "shards" within a document and summing up the "count" value from each shard to obtain the total.\u003c/p\u003e\n"],["\u003cp\u003eEach code sample requires the user to set up Application Default Credentials for Firestore authentication in their local development environment, which is further explained in the link provided.\u003c/p\u003e\n"],["\u003cp\u003eThe document also contains links to more detailed documentation on the topic of distributed counters to enhance the user's understanding of the use-case.\u003c/p\u003e\n"]]],[],null,["# Getting a Firestore document while using shards\n\nExplore further\n---------------\n\n\nFor detailed documentation that includes this code sample, see the following:\n\n- [Distributed counters](https://firebase.google.com/docs/firestore/solutions/counters)\n- [Support frequent and distributed counters](/firestore/native/docs/solutions/counters)\n\nCode sample\n-----------\n\n### C#\n\n\nTo authenticate to Firestore, set up Application Default Credentials.\nFor more information, see\n\n[Set up authentication for a local development environment](/docs/authentication/set-up-adc-local-dev-environment).\n\n /// \u003csummary\u003e\n /// Get total count across all shards.\n /// \u003c/summary\u003e\n /// \u003cparam name=\"docRef\"\u003eThe document reference \u003csee cref=\"DocumentReference\"/\u003e\u003c/param\u003e\n /// \u003creturns\u003eThe \u003csee cref=\"int\"/\u003e\u003c/returns\u003e\n private static async Task\u003cint\u003e GetCountAsync(DocumentReference docRef)\n {\n var snapshotList = await docRef.Collection(\"shards\").GetSnapshotAsync();\n return snapshotList.Sum(shard =\u003e shard.GetValue\u003cint\u003e(\"count\"));\n }\n\n### Go\n\n\nTo authenticate to Firestore, set up Application Default Credentials.\nFor more information, see\n\n[Set up authentication for a local development environment](/docs/authentication/set-up-adc-local-dev-environment).\n\n\n // getCount returns a total count across all shards.\n func (c *Counter) getCount(ctx context.Context, docRef *firestore.DocumentRef) (int64, error) {\n \tvar total int64\n \tshards := docRef.Collection(\"shards\").Documents(ctx)\n \tfor {\n \t\tdoc, err := shards.Next()\n \t\tif err == iterator.Done {\n \t\t\tbreak\n \t\t}\n \t\tif err != nil {\n \t\t\treturn 0, fmt.Errorf(\"Next: %w\", err)\n \t\t}\n\n \t\tvTotal := doc.Data()[\"Count\"]\n \t\tshardCount, ok := vTotal.(int64)\n \t\tif !ok {\n \t\t\treturn 0, fmt.Errorf(\"firestore: invalid dataType %T, want int64\", vTotal)\n \t\t}\n \t\ttotal += shardCount\n \t}\n \treturn total, nil\n }\n\n### Node.js\n\n\nTo authenticate to Firestore, set up Application Default Credentials.\nFor more information, see\n\n[Set up authentication for a local development environment](/docs/authentication/set-up-adc-local-dev-environment).\n\n async function getCount(docRef) {\n const querySnapshot = await docRef.collection('shards').get();\n const documents = querySnapshot.docs;\n\n let count = 0;\n for (const doc of documents) {\n count += doc.get('count');\n }\n return count;\n }\n\n### PHP\n\n\nTo authenticate to Firestore, set up Application Default Credentials.\nFor more information, see\n\n[Set up authentication for a local development environment](/docs/authentication/set-up-adc-local-dev-environment).\n\n $result = 0;\n $docCollection = $db-\u003ecollection('samples/php/distributedCounters')-\u003edocuments();\n foreach ($docCollection as $doc) {\n $result += $doc-\u003edata()['Cnt'];\n }\n\n### Python\n\n\nTo authenticate to Firestore, set up Application Default Credentials.\nFor more information, see\n\n[Set up authentication for a local development environment](/docs/authentication/set-up-adc-local-dev-environment).\n\n def get_count(self, doc_ref):\n \"\"\"Return a total count across all shards.\"\"\"\n total = 0\n shards = doc_ref.collection(\"shards\").list_documents()\n for shard in shards:\n total += shard.get().to_dict().get(\"count\", 0)\n return total\n\n### Ruby\n\n\nTo authenticate to Firestore, set up Application Default Credentials.\nFor more information, see\n\n[Set up authentication for a local development environment](/docs/authentication/set-up-adc-local-dev-environment).\n\n # project_id = \"Your Google Cloud Project ID\"\n # collection_path = \"shards\"\n\n require \"google/cloud/firestore\"\n\n firestore = Google::Cloud::https://cloud.google.com/ruby/docs/reference/google-cloud-firestore/latest/Google-Cloud-Firestore.html.https://cloud.google.com/ruby/docs/reference/google-cloud-firestore/latest/Google-Cloud-Firestore.html project_id: project_id\n\n shards_ref = firestore.https://cloud.google.com/ruby/docs/reference/google-cloud-firestore/latest/Google-Cloud-Firestore-Client.html collection_path\n\n count = 0\n shards_ref.get do |doc_ref|\n count += doc_ref[:count]\n end\n\n puts \"Count value is #{count}.\"\n\nWhat's next\n-----------\n\n\nTo search and filter code samples for other Google Cloud products, see the\n[Google Cloud sample browser](/docs/samples?product=firestore)."]]