Página por meio de uma coleção usando os SDKs do Microsoft Graph

Por motivos de desempenho, as coleções de entidades geralmente são divididas em páginas e cada página é retornada com uma URL para a próxima página. A classe PageIterator simplifica o consumo de coleções de páginas. O PageIterator manipula a enumeração da página atual e a solicitação de páginas subsequentes automaticamente.

Como alternativa, você pode usar a @odata.nextLink propriedade para solicitar manualmente páginas subsequentes.

Cabeçalhos de solicitação

Se você enviar cabeçalhos de solicitação adicionais em sua solicitação inicial, esses cabeçalhos não serão incluídos por padrão em solicitações de página subsequentes. Se esses cabeçalhos precisam ser enviados em solicitações subsequentes, você deve defini-los explicitamente.

Iterar em todas as mensagens

O exemplo a seguir mostra iterando todas as mensagens na caixa de correio de um usuário.

Dica

Este exemplo define um pequeno tamanho de página usando o top parâmetro para fins de demonstração. Você pode definir o tamanho da página até 999 para minimizar o número de solicitações necessárias.

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();

Ir

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();

Parar e retomar a iteração

Alguns cenários exigem interromper o processo de iteração para executar outras ações. É possível pausar a iteração retornando false do retorno de chamada de iteração. A iteração pode ser retomada chamando o resume método no PageIterator.

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();
}

Ir

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();
}

Solicitando manualmente páginas subsequentes

Como alternativa ao uso da classe PageIterator, você pode marcar manualmente a resposta de uma @odata.nextLink propriedade e solicitar a próxima página.

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;
    }
}

Ir

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;
  }
}