Durchblättern einer Sammlung mithilfe der Microsoft Graph SDKs

Aus Leistungsgründen werden Sammlungen von Entitäten häufig in Seiten aufgeteilt, und jede Seite wird mit einer URL zur nächsten Seite zurückgegeben. Die PageIterator-Klasse vereinfacht die Nutzung von ausgelagerten Sammlungen. PageIterator verarbeitet das Aufzählen der aktuellen Seite und das automatische Anfordern nachfolgender Seiten.

Alternativ können Sie die @odata.nextLink -Eigenschaft verwenden, um nachfolgende Seiten manuell anzufordern.

Anforderungsheader

Wenn Sie zusätzliche Anforderungsheader in Ihrer ursprünglichen Anforderung senden, werden diese Header nicht standardmäßig in nachfolgenden Seitenanforderungen eingeschlossen. Wenn diese Header bei nachfolgenden Anforderungen gesendet werden müssen, müssen Sie sie explizit festlegen.

Durchlaufen aller Nachrichten

Das folgende Beispiel zeigt das Durchlaufen aller Nachrichten im Postfach eines Benutzers.

Tipp

In diesem Beispiel wird eine kleine Seitengröße mit dem top -Parameter zu Demonstrationszwecken festgelegt. Sie können die Seitengröße auf 999 festlegen, um die Anzahl der erforderlichen Anforderungen zu minimieren.

C#

var messages = await graphClient.Me.Messages
    .GetAsync(requestConfiguration =>
    {
        requestConfiguration.QueryParameters.Top = 10;
        requestConfiguration.QueryParameters.Select =
            ["sender", "subject", "body"];
        requestConfiguration.Headers.Add(
            "Prefer", "outlook.body-content-type=\"text\"");
    });

if (messages == null)
{
    return;
}

var pageIterator = PageIterator<Message, MessageCollectionResponse>
    .CreatePageIterator(
        graphClient,
        messages,
        // Callback executed for each item in
        // the collection
        (msg) =>
        {
            Console.WriteLine(msg.Subject);
            return true;
        },
        // Used to configure subsequent page
        // requests
        (req) =>
        {
            // Re-add the header to subsequent requests
            req.Headers.Add("Prefer", "outlook.body-content-type=\"text\"");
            return req;
        });

await pageIterator.IterateAsync();

OK

import (
    "context"
    "fmt"
    "log"
    "time"

    abstractions "github.com/microsoft/kiota-abstractions-go"
    graph "github.com/microsoftgraph/msgraph-sdk-go"
    graphcore "github.com/microsoftgraph/msgraph-sdk-go-core"
    "github.com/microsoftgraph/msgraph-sdk-go/models"
    "github.com/microsoftgraph/msgraph-sdk-go/users"
)

headers := abstractions.NewRequestHeaders()
headers.Add("Prefer", "outlook.body-content-type=\"text\"")

var pageSize int32 = 10
query := users.ItemMessagesRequestBuilderGetQueryParameters{
    Select: []string{"body", "sender", "subject"},
    Top:    &pageSize,
}

options := users.ItemMessagesRequestBuilderGetRequestConfiguration{
    Headers:         headers,
    QueryParameters: &query,
}

result, err := graphClient.Me().Messages().Get(context.Background(), &options)
if err != nil {
    log.Fatalf("Error getting messages: %v\n", err)
}

// Initialize iterator
pageIterator, err := graphcore.NewPageIterator[*models.Message](
    result,
    graphClient.GetAdapter(),
    models.CreateMessageCollectionResponseFromDiscriminatorValue)
if err != nil {
    log.Fatalf("Error creating page iterator: %v\n", err)
}

// Any custom headers sent in original request should also be added
// to the iterator
pageIterator.SetHeaders(headers)

// Iterate over all pages
err = pageIterator.Iterate(
    context.Background(),
    func(message *models.Message) bool {
        fmt.Printf("%s\n", *message.GetSubject())
        // Return true to continue the iteration
        return true
    })
if err != nil {
    log.Fatalf("Error iterating over messages: %v\n", err)
}

Java

ArrayList<Message> messages = new ArrayList<>();

MessageCollectionResponse messageResponse = graphClient.me().messages().get( requestConfiguration -> {
    requestConfiguration.headers.add("Prefer", "outlook.body-content-type=\"text\"");
    requestConfiguration.queryParameters.select = new String[] {"sender, subject, body"};
    requestConfiguration.queryParameters.top = 10;
});

PageIterator<Message, MessageCollectionResponse> pageIterator =
        new PageIterator.Builder<Message, MessageCollectionResponse>()
        .client(graphClient)
        // Response from the first request
        .collectionPage(Objects.requireNonNull(messageResponse))
        // Factory to create a new collection response
        .collectionPageFactory(MessageCollectionResponse::createFromDiscriminatorValue)
        // Used to configure subsequent requests
        .requestConfigurator( requestInfo -> {
            // Re-add the header and query parameters to subsequent requests
            requestInfo.headers.add("Prefer", "outlook.body-content-type=\"text\"");
            requestInfo.addQueryParameter("%24select", new String[] {"sender, subject, body"});
            requestInfo.addQueryParameter("%24top", 10);
            return requestInfo;
        })
        // Callback executed for each item in the collection
        .processPageItemCallback( message -> {
            messages.add(message);
            return true;
        }).build();

pageIterator.iterate();

PHP

$query = new MessagesRequestBuilderGetQueryParameters(
    top: 10,
    select: ['sender', 'subject', 'body']);

$config = new MessagesRequestBuilderGetRequestConfiguration(
    queryParameters: $query,
    headers: ['Prefer' => 'outlook.body-content-type="text"']);

$messages = $graphClient->me()
    ->messages()
    ->get($config)
    ->wait();

// Microsoft\Graph\Core\Tasks\PageIterator
$pageIterator = new PageIterator($messages, $graphClient->getRequestAdapter());

$callback = function($message): bool {
    /** @var Models\Message $message */
    print($message->getSubject().PHP_EOL);
    // Return true to continue iteration
    return true;
};

// Re-add the header to subsequent requests
$pageIterator->setHeaders(['Prefer' => 'outlook.body-content-type="text"']);

$pageIterator->iterate($callback);

TypeScript

const response: PageCollection = await graphClient
  .api('/me/messages?$top=10&$select=sender,subject,body')
  .header('Prefer', 'outlook.body-content-type="text"')
  .get();

// A callback function to be called for every item in the collection.
// This call back should return boolean indicating whether not to
// continue the iteration process.
const callback: PageIteratorCallback = (message: Message) => {
  console.log(message.subject);
  return true;
};

// A set of request options to be applied to
// all subsequent page requests
const requestOptions: GraphRequestOptions = {
  // Re-add the header to subsequent requests
  headers: {
    Prefer: 'outlook.body-content-type="text"',
  },
};

// Creating a new page iterator instance with client a graph client
// instance, page collection response from request and callback
const pageIterator = new PageIterator(
  graphClient,
  response,
  callback,
  requestOptions,
);

// This iterates the collection until the nextLink is drained out.
await pageIterator.iterate();

Beenden und Fortsetzen der Iteration

Einige Szenarien erfordern das Beenden des Iterationsprozesses, um andere Aktionen ausführen zu können. Es ist möglich, die Iteration anzuhalten, indem vom Iterationsrückruf zurückgegeben false wird. Die Iteration kann fortgesetzt werden, indem die resume -Methode für den PageIterator aufgerufen wird.

C#

int count = 0;
int pauseAfter = 25;

var messages = await graphClient.Me.Messages
    .GetAsync(requestConfiguration =>
    {
        requestConfiguration.QueryParameters.Top = 10;
        requestConfiguration.QueryParameters.Select =
            ["sender", "subject"];
    });

if (messages == null)
{
    return;
}

var pageIterator = PageIterator<Message, MessageCollectionResponse>
    .CreatePageIterator(
        graphClient,
        messages,
        (msg) =>
        {
            Console.WriteLine(msg.Subject);
            count++;
            // If we've iterated over the limit,
            // stop the iteration by returning false
            return count < pauseAfter;
        });

await pageIterator.IterateAsync();

while (pageIterator.State != PagingState.Complete)
{
    Console.WriteLine("Iteration paused for 5 seconds...");
    await Task.Delay(5000);
    // Reset count
    count = 0;
    await pageIterator.ResumeAsync();
}

OK

import (
    "context"
    "fmt"
    "log"
    "time"

    abstractions "github.com/microsoft/kiota-abstractions-go"
    graph "github.com/microsoftgraph/msgraph-sdk-go"
    graphcore "github.com/microsoftgraph/msgraph-sdk-go-core"
    "github.com/microsoftgraph/msgraph-sdk-go/models"
    "github.com/microsoftgraph/msgraph-sdk-go/users"
)

var pageSize int32 = 10
query := users.ItemMessagesRequestBuilderGetQueryParameters{
    Select: []string{"body", "sender", "subject"},
    Top:    &pageSize,
}

options := users.ItemMessagesRequestBuilderGetRequestConfiguration{
    QueryParameters: &query,
}

result, err := graphClient.Me().Messages().Get(context.Background(), &options)
if err != nil {
    log.Fatalf("Error getting messages: %v\n", err)
}

// Initialize iterator
pageIterator, err := graphcore.NewPageIterator[*models.Message](
    result,
    graphClient.GetAdapter(),
    models.CreateMessageCollectionResponseFromDiscriminatorValue)
if err != nil {
    log.Fatalf("Error creating page iterator: %v\n", err)
}

// Pause iterating after 25
var count, pauseAfter = 0, 25

// Iterate over all pages
err = pageIterator.Iterate(
    context.Background(),
    func(message *models.Message) bool {
        count++
        fmt.Printf("%d: %s\n", count, *message.GetSubject())
        // Once count = 25, this returns false,
        // Which pauses the iteration
        return count < pauseAfter
    })
if err != nil {
    log.Fatalf("Error iterating over messages: %v\n", err)
}

// Pause 5 seconds
fmt.Printf("Iterated first %d messages, pausing for 5 seconds...\n", pauseAfter)
time.Sleep(5 * time.Second)
fmt.Printf("Resuming iteration...\n")

// Resume iteration
err = pageIterator.Iterate(
    context.Background(),
    func(message *models.Message) bool {
        count++
        fmt.Printf("%d: %s\n", count, *message.GetSubject())
        // Return true to continue the iteration
        return true
    })
if err != nil {
    log.Fatalf("Error iterating over messages: %v\n", err)
}

Java

int iterations = 1;
ArrayList<Message> messages = new ArrayList<>();
int pauseAfter = iterations*25;

MessageCollectionResponse messageResponse = graphClient.me().messages().get( requestConfiguration -> {
    requestConfiguration.queryParameters.top = 10;
    requestConfiguration.queryParameters.select = new String[] {"sender, subject"};
});

PageIterator<Message, MessageCollectionResponse> pageIterator =
        new PageIterator.Builder<Message, MessageCollectionResponse>()
        .client(graphClient)
        .collectionPage(Objects.requireNonNull(messageResponse))
        .collectionPageFactory(MessageCollectionResponse::createFromDiscriminatorValue)
        .requestConfigurator( requestInfo -> {
            requestInfo.addQueryParameter("%24select", new String[] {"sender, subject"});
            requestInfo.addQueryParameter("%24top", 10);
            return requestInfo;
        })
        .processPageItemCallback( message -> {
            messages.add(message);
            // Pause paging by returning false after 25 messages
            return messages.size() < pauseAfter;
        }).build();

pageIterator.iterate();

// Resume paging
while (pageIterator.getPageIteratorState() != PageIterator.PageIteratorState.COMPLETE) {
    iterations+=1;
    pageIterator.resume();
}

PHP

$count = 0;

$messages = $graphClient->me()
    ->messages()
    ->get()
    ->wait();

// Microsoft\Graph\Core\Tasks\PageIterator
$pageIterator = new PageIterator($messages, $graphClient->getRequestAdapter());

$callback = function($message) use (&$count): bool {
    /** @var Models\Message $message */
    $count++;
    print($count.'. '.$message->getSubject().PHP_EOL);
    // Return true to continue iteration
    // Return false once first 5 have been processed
    return $count < 5;
};

$pageIterator->iterate($callback);

print('Pausing iteration after first 5'.PHP_EOL);
sleep(5);

// Process next 5
$count = 0;
$pageIterator->iterate($callback);

TypeScript

let count = 0;
const pauseAfter = 25;

const response: PageCollection = await graphClient
  .api('/me/messages?$top=10&$select=sender,subject,body')
  .get();

const callback: PageIteratorCallback = (message: Message) => {
  console.log(message.subject);
  count++;

  // If we've iterated over the limit,
  // stop the iteration by returning false
  return count < pauseAfter;
};

const pageIterator = new PageIterator(graphClient, response, callback);
await pageIterator.iterate();

while (!pageIterator.isComplete()) {
  console.log('Iteration paused for 5 seconds...');
  await new Promise((resolve) => setTimeout(resolve, 5000));

  // Reset count
  count = 0;
  await pageIterator.resume();
}

Manuelles Anfordern nachfolgender Seiten

Als Alternative zur Verwendung der PageIterator-Klasse können Sie die Antwort für eine @odata.nextLink Eigenschaft manuell überprüfen und die nächste Seite anfordern.

C#

var messages = await graphClient.Me.Messages
    .GetAsync(requestConfiguration =>
    {
        requestConfiguration.QueryParameters.Top = 10;
    });

while (messages?.Value != null)
{
    foreach (var message in messages.Value)
    {
        Console.WriteLine(message.Subject);
    }

    // If OdataNextLink has a value, there is another page
    if (!string.IsNullOrEmpty(messages.OdataNextLink))
    {
        // Pass the OdataNextLink to the WithUrl method
        // to request the next page
        messages = await graphClient.Me.Messages
            .WithUrl(messages.OdataNextLink)
            .GetAsync();
    }
    else
    {
        // No more results, exit loop
        break;
    }
}

OK

import (
    "context"
    "fmt"
    "log"
    "time"

    abstractions "github.com/microsoft/kiota-abstractions-go"
    graph "github.com/microsoftgraph/msgraph-sdk-go"
    graphcore "github.com/microsoftgraph/msgraph-sdk-go-core"
    "github.com/microsoftgraph/msgraph-sdk-go/models"
    "github.com/microsoftgraph/msgraph-sdk-go/users"
)

var pageSize int32 = 10
query := users.ItemMessagesRequestBuilderGetQueryParameters{
    Top: &pageSize,
}

options := users.ItemMessagesRequestBuilderGetRequestConfiguration{
    QueryParameters: &query,
}

result, err := graphClient.Me().Messages().Get(context.Background(), &options)
if err != nil {
    log.Fatalf("Error getting messages: %v\n", err)
}

for {
    for _, message := range result.GetValue() {
        fmt.Printf("%s\n", *message.GetSubject())
    }

    nextPageUrl := result.GetOdataNextLink()
    if nextPageUrl != nil {
        result, err = graphClient.Me().Messages().
            WithUrl(*nextPageUrl).
            Get(context.Background(), nil)
        if err != nil {
            log.Fatalf("Error getting messages: %v\n", err)
        }
    } else {
        break
    }
}

Java

MessageCollectionResponse messagesPage = graphClient.me().messages().get( requestConfiguration -> {
    requestConfiguration.headers.add("Prefer", "outlook.body-content-type=\"text\"");
    requestConfiguration.queryParameters.select = new String[] {"sender, subject, body"};
    requestConfiguration.queryParameters.top = 10;
});

while (messagesPage != null) {
    final List<Message> messages = messagesPage.getValue();
    for (Message message : messages) {
        System.out.println(message.getSubject());
    }

    // Get the next page
    final String odataNextLink = messagesPage.getOdataNextLink();
    if (odataNextLink == null || odataNextLink.isEmpty()) {
        break;
    } else {
        messagesPage = graphClient.me().messages().withUrl(odataNextLink).get();
    }
}

PHP

/** @var MessageCollectionResponse $messages */
$messages = $graphClient->me()
    ->messages()
    ->get()
    ->wait();

while (null !== $messages->getValue())
{
    foreach($messages->getValue() as $message) {
        /** @var Models\Message $message */
        print($message->getSubject().PHP_EOL);
    }

    if (null !== $messages->getOdataNextLink()) {
        $messages = $graphClient->me()
            ->messages()
            ->withUrl($messages->getOdataNextLink())
            ->get()
            ->wait();
    }
    else {
        break;
    }
}

TypeScript

let response: PageCollection = await graphClient
  .api('/me/messages?$top=10')
  .get();

while (response.value.length > 0) {
  for (const message of response.value as Message[]) {
    console.log(message.subject);
  }

  if (response['@odata.nextLink']) {
    response = await graphClient.api(response['@odata.nextLink']).get();
  } else {
    break;
  }
}