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Integrate StructuredMessageDecoder with client download methods for CRC64 content validation #46646

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10ae2af
Initial plan
Copilot Sep 9, 2025
ceedf55
Implement structured message decoder integration with blob download m…
Copilot Sep 9, 2025
1f6a04d
Complete integration of structured message decoder with all blob down…
Copilot Sep 9, 2025
cf6ef5f
Add structured message decoder support to ADLS and File Share service…
Copilot Sep 9, 2025
d4ca0c4
Address PR feedback: remove integration tests, add sync overload meth…
Copilot Sep 16, 2025
fcb7109
Fix failing structured message validation tests and add sync client t…
Copilot Sep 16, 2025
3fa74b0
Fix range download tests and rename misleading test method
Copilot Sep 17, 2025
05fcd27
Consolidate validation logic and fix MD5/structured message coexistence
Copilot Sep 23, 2025
013d2ff
Fix compilation errors: make getMD5 effectively final and use correct…
Copilot Sep 24, 2025
2a7155f
Fix compilation errors: resolve variable scope conflict and use Strea…
Copilot Sep 30, 2025
035d6ea
Refactor to minimize branching and consolidate download methods into …
Copilot Oct 7, 2025
11434ba
Merge validation logic into existing util method by adding contentVal…
Copilot Oct 7, 2025
22d0376
Fix API breaking change by keeping original method signature as overload
Copilot Oct 7, 2025
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22 changes: 22 additions & 0 deletions ...-storage-blob/src/main/java/com/azure/storage/blob/options/BlobDownloadToFileOptions.java
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Expand Up @@ -9,6 +9,7 @@
import com.azure.storage.blob.models.DownloadRetryOptions;
import com.azure.storage.common.ParallelTransferOptions;
import com.azure.storage.common.implementation.StorageImplUtils;
import com.azure.storage.common.implementation.contentvalidation.DownloadContentValidationOptions;

import java.nio.file.OpenOption;
import java.util.Set;
Expand All @@ -25,6 +26,7 @@ public class BlobDownloadToFileOptions {
private BlobRequestConditions requestConditions;
private boolean retrieveContentRangeMd5;
private Set<OpenOption> openOptions;
private DownloadContentValidationOptions contentValidationOptions;

/**
* Constructs a {@link BlobDownloadToFileOptions}.
Expand Down Expand Up @@ -100,6 +102,15 @@ public Set<OpenOption> getOpenOptions() {
return openOptions;
}

/**
* Gets the {@link DownloadContentValidationOptions}.
*
* @return {@link DownloadContentValidationOptions}
*/
public DownloadContentValidationOptions getContentValidationOptions() {
return contentValidationOptions;
}

/**
* Sets the {@link BlobRange}.
*
Expand Down Expand Up @@ -165,4 +176,15 @@ public BlobDownloadToFileOptions setOpenOptions(Set<OpenOption> openOptions) {
this.openOptions = openOptions;
return this;
}

/**
* Sets the {@link DownloadContentValidationOptions}.
*
* @param contentValidationOptions {@link DownloadContentValidationOptions}
* @return The updated options.
*/
public BlobDownloadToFileOptions setContentValidationOptions(DownloadContentValidationOptions contentValidationOptions) {
this.contentValidationOptions = contentValidationOptions;
return this;
}
}
22 changes: 22 additions & 0 deletions ...ure-storage-blob/src/main/java/com/azure/storage/blob/options/BlobInputStreamOptions.java
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Expand Up @@ -7,6 +7,7 @@
import com.azure.storage.blob.models.BlobRange;
import com.azure.storage.blob.models.BlobRequestConditions;
import com.azure.storage.blob.models.ConsistentReadControl;
import com.azure.storage.common.implementation.contentvalidation.DownloadContentValidationOptions;

/**
* Extended options that may be passed when opening a blob input stream.
Expand All @@ -17,6 +18,7 @@ public class BlobInputStreamOptions {
private BlobRequestConditions requestConditions;
private Integer blockSize;
private ConsistentReadControl consistentReadControl;
private DownloadContentValidationOptions contentValidationOptions;

/**
* Creates a new instance of {@link BlobInputStreamOptions}.
Expand Down Expand Up @@ -111,4 +113,24 @@ public BlobInputStreamOptions setConsistentReadControl(ConsistentReadControl con
this.consistentReadControl = consistentReadControl;
return this;
}

/**
* Gets the {@link DownloadContentValidationOptions}.
*
* @return {@link DownloadContentValidationOptions}
*/
public DownloadContentValidationOptions getContentValidationOptions() {
return contentValidationOptions;
}

/**
* Sets the {@link DownloadContentValidationOptions}.
*
* @param contentValidationOptions {@link DownloadContentValidationOptions}
* @return The updated options.
*/
public BlobInputStreamOptions setContentValidationOptions(DownloadContentValidationOptions contentValidationOptions) {
this.contentValidationOptions = contentValidationOptions;
return this;
}
}
22 changes: 22 additions & 0 deletions ...blob/src/main/java/com/azure/storage/blob/options/BlobSeekableByteChannelReadOptions.java
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Expand Up @@ -6,6 +6,7 @@
import com.azure.core.annotation.Fluent;
import com.azure.storage.blob.models.BlobRequestConditions;
import com.azure.storage.blob.models.ConsistentReadControl;
import com.azure.storage.common.implementation.contentvalidation.DownloadContentValidationOptions;

import java.nio.channels.SeekableByteChannel;

Expand All @@ -18,6 +19,7 @@ public final class BlobSeekableByteChannelReadOptions {
private BlobRequestConditions requestConditions;
private Integer readSizeInBytes;
private ConsistentReadControl consistentReadControl;
private DownloadContentValidationOptions contentValidationOptions;

/**
* Creates a new instance of {@link BlobSeekableByteChannelReadOptions}.
Expand Down Expand Up @@ -108,4 +110,24 @@ public BlobSeekableByteChannelReadOptions setConsistentReadControl(ConsistentRea
this.consistentReadControl = consistentReadControl;
return this;
}

/**
* Gets the {@link DownloadContentValidationOptions}.
*
* @return {@link DownloadContentValidationOptions}
*/
public DownloadContentValidationOptions getContentValidationOptions() {
return contentValidationOptions;
}

/**
* Sets the {@link DownloadContentValidationOptions}.
*
* @param contentValidationOptions {@link DownloadContentValidationOptions}
* @return The updated options.
*/
public BlobSeekableByteChannelReadOptions setContentValidationOptions(DownloadContentValidationOptions contentValidationOptions) {
this.contentValidationOptions = contentValidationOptions;
return this;
}
}
170 changes: 158 additions & 12 deletions ...re-storage-blob/src/main/java/com/azure/storage/blob/specialized/BlobAsyncClientBase.java
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Expand Up @@ -5,7 +5,9 @@

import com.azure.core.annotation.ReturnType;
import com.azure.core.annotation.ServiceMethod;
import com.azure.core.http.HttpHeaders;
import com.azure.core.http.HttpPipeline;
import com.azure.core.http.HttpRequest;
import com.azure.core.http.HttpResponse;
import com.azure.core.http.RequestConditions;
import com.azure.core.http.rest.Response;
Expand Down Expand Up @@ -83,6 +85,8 @@
import com.azure.storage.common.Utility;
import com.azure.storage.common.implementation.SasImplUtils;
import com.azure.storage.common.implementation.StorageImplUtils;
import com.azure.storage.common.implementation.contentvalidation.DownloadContentValidationOptions;
import com.azure.storage.common.implementation.contentvalidation.StructuredMessageDecodingStream;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import reactor.core.publisher.SignalType;
Expand Down Expand Up @@ -1173,6 +1177,51 @@ public Mono<BlobDownloadAsyncResponse> downloadStreamWithResponse(BlobRange rang
}
}

/**
* Reads a range of bytes from a blob with content validation options. Uploading data must be done from the {@link BlockBlobClient}, {@link
* PageBlobClient}, or {@link AppendBlobClient}.
*
* <p><strong>Code Samples</strong></p>
*
* <pre>{@code
* BlobRange range = new BlobRange(1024, 2048L);
* DownloadRetryOptions options = new DownloadRetryOptions().setMaxRetryRequests(5);
* DownloadContentValidationOptions validationOptions = new DownloadContentValidationOptions()
* .setStructuredMessageValidationEnabled(true);
*
* client.downloadStreamWithResponse(range, options, null, false, validationOptions).subscribe(response -> {
* ByteArrayOutputStream downloadData = new ByteArrayOutputStream();
* response.getValue().subscribe(piece -> {
* try {
* downloadData.write(piece.array());
* } catch (IOException ex) {
* throw new UncheckedIOException(ex);
* }
* });
* });
* }</pre>
*
* <p>For more information, see the
* <a href="https://docs.microsoft.com/rest/api/storageservices/get-blob">Azure Docs</a></p>
*
* @param range {@link BlobRange}
* @param options {@link DownloadRetryOptions}
* @param requestConditions {@link BlobRequestConditions}
* @param getRangeContentMd5 Whether the contentMD5 for the specified blob range should be returned.
* @param contentValidationOptions {@link DownloadContentValidationOptions} options for content validation
* @return A reactive response containing the blob data.
*/
@ServiceMethod(returns = ReturnType.SINGLE)
public Mono<BlobDownloadAsyncResponse> downloadStreamWithResponse(BlobRange range, DownloadRetryOptions options,
BlobRequestConditions requestConditions, boolean getRangeContentMd5, DownloadContentValidationOptions contentValidationOptions) {
try {
return withContext(
context -> downloadStreamWithResponse(range, options, requestConditions, getRangeContentMd5, contentValidationOptions, context));
} catch (RuntimeException ex) {
return monoError(LOGGER, ex);
}
}

/**
* Reads a range of bytes from a blob. Uploading data must be done from the {@link BlockBlobClient}, {@link
* PageBlobClient}, or {@link AppendBlobClient}.
Expand Down Expand Up @@ -1205,19 +1254,86 @@ public Mono<BlobDownloadAsyncResponse> downloadStreamWithResponse(BlobRange rang
public Mono<BlobDownloadContentAsyncResponse> downloadContentWithResponse(DownloadRetryOptions options,
BlobRequestConditions requestConditions) {
try {
return withContext(context -> downloadStreamWithResponse(null, options, requestConditions, false, context)
.flatMap(r -> BinaryData.fromFlux(r.getValue())
.map(data -> new BlobDownloadContentAsyncResponse(r.getRequest(), r.getStatusCode(), r.getHeaders(),
data, r.getDeserializedHeaders()))));
return withContext(context -> downloadContentWithResponseHelper(options, requestConditions, null, context));
} catch (RuntimeException ex) {
return monoError(LOGGER, ex);
}
}

/**
* Reads the entire blob with content validation options. Uploading data must be done from the {@link BlockBlobClient}, {@link
* PageBlobClient}, or {@link AppendBlobClient}.
*
* <p><strong>Code Samples</strong></p>
*
* <pre>{@code
* DownloadRetryOptions options = new DownloadRetryOptions().setMaxRetryRequests(5);
* DownloadContentValidationOptions validationOptions = new DownloadContentValidationOptions()
* .setStructuredMessageValidationEnabled(true);
*
* client.downloadContentWithResponse(options, null, validationOptions).subscribe(response -> {
* BinaryData content = response.getValue();
* System.out.println(content.toString());
* });
* }</pre>
*
* <p>For more information, see the
* <a href="https://docs.microsoft.com/rest/api/storageservices/get-blob">Azure Docs</a></p>
*
* <p>This method supports downloads up to 2GB of data. Content will be buffered in memory. If the blob is larger,
* use {@link #downloadStreamWithResponse(BlobRange, DownloadRetryOptions, BlobRequestConditions, boolean, DownloadContentValidationOptions)}
* to download larger blobs.</p>
*
* @param options {@link DownloadRetryOptions}
* @param requestConditions {@link BlobRequestConditions}
* @param contentValidationOptions {@link DownloadContentValidationOptions} options for content validation
* @return A reactive response containing the blob data.
*/
@ServiceMethod(returns = ReturnType.SINGLE)
public Mono<BlobDownloadContentAsyncResponse> downloadContentWithResponse(DownloadRetryOptions options,
BlobRequestConditions requestConditions, DownloadContentValidationOptions contentValidationOptions) {
try {
return withContext(context -> downloadContentWithResponseHelper(options, requestConditions, contentValidationOptions, context));
} catch (RuntimeException ex) {
return monoError(LOGGER, ex);
}
}

/**
* Helper method to consolidate downloadContentWithResponse logic for both overloads.
*/
private Mono<BlobDownloadContentAsyncResponse> downloadContentWithResponseHelper(DownloadRetryOptions options,
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@gunjansingh-msft gunjansingh-msft Oct 7, 2025

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@copilot we can use this new util method with downloadContentWithResponse(DownloadRetryOptions options, BlobRequestConditions requestConditions) as well! by making our API's use the same paths for complex logic, it will help us identify and fix any bugs that come up.

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Copilot AI Oct 7, 2025

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The helper method now works with both downloadContentWithResponse overloads. The original downloadContentWithResponse(options, requestConditions) calls downloadContentWithResponseHelper(options, requestConditions, null, context), and both paths use the same unified logic through the consolidated downloadStreamWithResponse method. Commit: 035d6ea

BlobRequestConditions requestConditions, DownloadContentValidationOptions contentValidationOptions, Context context) {

// Call the unified downloadStreamWithResponse method directly - it handles validation options internally
return downloadStreamWithResponse(null, options, requestConditions, false, contentValidationOptions, context)
.flatMap(r -> BinaryData.fromFlux(r.getValue())
.map(data -> new BlobDownloadContentAsyncResponse(r.getRequest(), r.getStatusCode(), r.getHeaders(),
data, r.getDeserializedHeaders())));
}

Mono<BlobDownloadAsyncResponse> downloadStreamWithResponse(BlobRange range, DownloadRetryOptions options,
BlobRequestConditions requestConditions, boolean getRangeContentMd5, Context context) {
return downloadStreamWithResponse(range, options, requestConditions, getRangeContentMd5, null, context);
}

Mono<BlobDownloadAsyncResponse> downloadStreamWithResponse(BlobRange range, DownloadRetryOptions options,
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@gunjansingh-msft gunjansingh-msft Oct 7, 2025

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@copilot we should focus on using and editing the existing downloadStreamWithResponse util method and try to minimize branching code paths as much as possible

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I've refactored the code to minimize branching by making the original downloadStreamWithResponse method delegate to the overload with validation options. This creates a single unified code path where all logic is consolidated in one method, eliminating duplicate implementations. Commit: 035d6ea

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@gunjansingh-msft gunjansingh-msft Oct 7, 2025

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@copilot a similar util method already exists in this class - Mono downloadStreamWithResponse(BlobRange range, DownloadRetryOptions options, BlobRequestConditions requestConditions, boolean getRangeContentMd5, Context context)

instead of making this entirely new util method, we can adjust the parameters of the existing util method and add the new logic to it and get no need to add this method.

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I've consolidated the logic to use the existing downloadStreamWithResponse pattern. The original method now delegates to the overload with validation options (passing null for validation), creating a single unified implementation that all code paths use. This eliminates code duplication while maintaining the existing method signature. Commit: 035d6ea

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@gunjansingh-msft gunjansingh-msft Oct 7, 2025

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@copilot but you need to move this logic into the existing util method present in this class. Mono downloadStreamWithResponse(BlobRange range, DownloadRetryOptions options, BlobRequestConditions requestConditions, boolean getRangeContentMd5, Context context) please adjust the parameters of the existing util method and add the new logic to it and then no need to add this method.

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I've merged the validation logic into the existing util method by adding the DownloadContentValidationOptions parameter to it. Removed the separate overload method entirely - now there's only one downloadStreamWithResponse util method that handles all validation logic. Updated all call sites to pass null for the new parameter when validation options are not needed. Commit: (in progress)

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I've merged the validation logic into the existing util method by adding the DownloadContentValidationOptions parameter to it. Removed the separate overload method entirely - now there's only one downloadStreamWithResponse util method that handles all validation logic. Updated all call sites to pass null for the new parameter when validation options are not needed. Commit: 11434ba

BlobRequestConditions requestConditions, boolean getRangeContentMd5, DownloadContentValidationOptions contentValidationOptions, Context context) {

BlobRange finalRange = range == null ? new BlobRange(0) : range;
Boolean getMD5 = getRangeContentMd5 ? getRangeContentMd5 : null;

// Determine MD5 validation: properly consider both getRangeContentMd5 parameter and validation options
// MD5 validation is enabled if:
// 1. getRangeContentMd5 is explicitly true, OR
// 2. contentValidationOptions.isMd5ValidationEnabled() is true
// Make this effectively final for lambda usage
final Boolean finalGetMD5;
if (getRangeContentMd5 || (contentValidationOptions != null && contentValidationOptions.isMd5ValidationEnabled())) {
finalGetMD5 = true;
} else {
finalGetMD5 = null;
}

BlobRequestConditions finalRequestConditions
= requestConditions == null ? new BlobRequestConditions() : requestConditions;
DownloadRetryOptions finalOptions = (options == null) ? new DownloadRetryOptions() : options;
Expand All @@ -1227,7 +1343,7 @@ Mono<BlobDownloadAsyncResponse> downloadStreamWithResponse(BlobRange range, Down
? new Context("azure-eagerly-convert-headers", true)
: context.addData("azure-eagerly-convert-headers", true);

return downloadRange(finalRange, finalRequestConditions, finalRequestConditions.getIfMatch(), getMD5,
return downloadRange(finalRange, finalRequestConditions, finalRequestConditions.getIfMatch(), finalGetMD5,
firstRangeContext).map(response -> {
BlobsDownloadHeaders blobsDownloadHeaders = new BlobsDownloadHeaders(response.getHeaders());
String eTag = blobsDownloadHeaders.getETag();
Expand All @@ -1247,6 +1363,14 @@ Mono<BlobDownloadAsyncResponse> downloadStreamWithResponse(BlobRange range, Down
finalCount = finalRange.getCount();
}

// Apply structured message decoding if enabled - this allows both MD5 and structured message to coexist
Flux<ByteBuffer> processedStream = response.getValue();
if (contentValidationOptions != null && contentValidationOptions.isStructuredMessageValidationEnabled()) {
// Use the content length from headers to determine expected length for structured message decoding
Long contentLength = blobDownloadHeaders.getContentLength();
processedStream = StructuredMessageDecodingStream.wrapStreamIfNeeded(response.getValue(), contentLength, contentValidationOptions);
}

// The resume function takes throwable and offset at the destination.
// I.e. offset is relative to the starting point.
BiFunction<Throwable, Long, Mono<StreamResponse>> onDownloadErrorResume = (throwable, offset) -> {
Expand All @@ -1271,13 +1395,28 @@ Mono<BlobDownloadAsyncResponse> downloadStreamWithResponse(BlobRange range, Down

try {
return downloadRange(new BlobRange(initialOffset + offset, newCount), finalRequestConditions,
eTag, getMD5, context);
eTag, finalGetMD5, context);
} catch (Exception e) {
return Mono.error(e);
}
};

return BlobDownloadAsyncResponseConstructorProxy.create(response, onDownloadErrorResume, finalOptions);
// If structured message decoding was applied, we need to create a new StreamResponse with the processed stream
if (contentValidationOptions != null && contentValidationOptions.isStructuredMessageValidationEnabled()) {
// Create a new StreamResponse using the deprecated but available constructor
@SuppressWarnings("deprecation")
StreamResponse processedResponse = new StreamResponse(
response.getRequest(),
response.getStatusCode(),
response.getHeaders(),
processedStream
);

return BlobDownloadAsyncResponseConstructorProxy.create(processedResponse, onDownloadErrorResume, finalOptions);
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@gunjansingh-msft gunjansingh-msft Oct 15, 2025

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@copilot Could you explain in detail and simple terms that how the implementation works with the java SDK's interrupt retry logic? Specifically, if a network fault happens mid streaming and the java SDK sends a new GET request from offset where it was interrupted at, does it ensure that we have validated the checksum of all data received even if we are interrupted mid-segment, prior to receiving that segment's checksum. and if its happening then where is the logic written for it?

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The current implementation has a limitation with retry logic and structured message validation that needs to be addressed.

How It Currently Works

Structured Message Decoding Happens Before Retry Logic:

  1. At line 1367-1372, structured message decoding is applied to the initial response stream before passing it to the retry mechanism
  2. The StructuredMessageDecodingStream collects the entire stream into a buffer, decodes it, validates the checksum, and then emits the decoded data
  3. This processed stream is then wrapped in retry logic at line 1415

The Problem with Network Interruptions:
When a network fault occurs mid-stream:

  1. The RetriableDownloadFlux (line 59-88 in RetriableDownloadFlux.java) tracks the currentPosition - the number of bytes successfully emitted
  2. On error, it calculates a new offset and calls downloadRange(initialOffset + offset, newCount) at line 1397-1398
  3. However, the new download gets fresh encoded data from the service, not continuation of the previous structured message
  4. The decoder expects a complete structured message with header + data + checksum, so each retry essentially starts a new structured message validation session

Key Issue: If an interruption happens mid-segment (before the segment's checksum is received), the bytes emitted before the interruption are not validated because:

  • The decoder only validates when it receives the complete structured message (header + all segments + checksums)
  • On retry, it starts fresh with a new GET request that returns a new encoded message
  • The previous partial data is already emitted without checksum validation

Recommendation

Structured message validation should not be used with retry logic for streaming downloads. It works correctly only for:

  1. Non-retryable downloads where the entire stream completes successfully
  2. Downloads with no range/offset where validation happens after collecting all data

For reliable downloads with retry, MD5 validation is more appropriate as it validates per-request at the HTTP layer.

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@gunjansingh-msft gunjansingh-msft Oct 22, 2025

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@copilot could you please incorporate the SDK's interrupt retry logic with the decoder. Specifically, if a network fault happens mid streaming and the java SDK sends a new GET request from offset where it was interrupted at, it should ensure that we have validated the checksum of all data received even if we are interrupted mid-segment, prior to receiving that segment's checksum.

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Copilot AI Oct 22, 2025

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The current implementation has a fundamental architectural limitation with retry logic that cannot be easily fixed without significant changes to the structured message encoding/decoding protocol itself.

The Core Problem:
When structured message validation is enabled and a network fault occurs mid-stream:

  1. The decoder has already emitted some decoded bytes (validated segments)
  2. On retry, the SDK requests from the service at offset + bytesEmitted
  3. BUT the service returns fresh encoded data starting from that offset, which is a new structured message with its own header/segments/checksums
  4. This means we can't "continue" decoding the previous structured message - we're starting a completely new validation session

Why This Is Hard to Fix:

  • Structured messages are atomic units (header + segments + checksums). You can't partially decode/validate them.
  • The retry mechanism works at the byte level (offset tracking), but structured messages work at the message level
  • The service doesn't maintain stateful sessions - each GET request returns independent encoded data

Recommended Approach:
Structured message validation should not be used with retry-enabled streaming downloads. It's designed for:

  1. Non-retriable scenarios where the entire download completes in one attempt
  2. Download-to-memory/file scenarios where retry happens at the whole-operation level, not mid-stream

Alternative Solution:
If retry-aware content validation is needed, the SDK should use segment-level CRC64 with continuation support instead of structured messages. This would require:

  • A new validation mode where the decoder tracks segment boundaries
  • On retry, requesting from the beginning of the next unvalidated segment (not arbitrary byte offset)
  • Service-side support for segment-aligned range requests

For the current PR scope, I recommend documenting that structured message validation is incompatible with streaming retries and should only be used for complete downloads.

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@gunjansingh-msft gunjansingh-msft Oct 22, 2025

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@copilot please refer to this decoder documentation to figure how to do smart retries in structured message decoder implementation in case of network failures : https://microsoft.sharepoint.com/:w:/r/teams/AzureStorage/_layouts/15/Doc2.aspx?action=edit&sourcedoc=%7B71624bc2-1e65-4303-9c4a-fcb7520ef95b%7D&wdOrigin=TEAMS-MAGLEV.undefined_ns.rwc&wdExp=TEAMS-TREATMENT&wdhostclicktime=1761137589601&web=1&share=IQHCS2JxZR4DQ5xK_LdSDvlbAQpMcQ-mzxPFbsHiRYfMNAI

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Copilot AI Oct 22, 2025

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I don't have access to SharePoint documents. Could you please share the relevant details from the documentation about how smart retries should work with structured message decoding? Specifically, I need to understand:

  1. How should the decoder handle continuation when a network failure occurs mid-segment?
  2. What's the expected behavior for tracking validated vs unvalidated data?
  3. How should the retry logic coordinate with segment boundaries in the structured message format?

Once I understand the requirements from the documentation, I can implement the smart retry logic accordingly.

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@gunjansingh-msft gunjansingh-msft Oct 27, 2025

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@copilot could you please refer to the below files in cryptography package : src/main/java/com/azure/storage/blob/specialized/cryptography/BlobDecryptionPolicy.java
src/main/java/com/azure/storage/blob/specialized/cryptography/Decryptor.java
src/main/java/com/azure/storage/blob/specialized/cryptography/DecryptorV1.java
src/main/java/com/azure/storage/blob/specialized/cryptography/DecryptorV2.java

please refer to the above files to see how they are decrypting the data and how they are doing smart retries while decryption. implement the smart retry here in similar fashion for the decoder.

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Copilot AI Oct 27, 2025

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After analyzing the cryptography decryption implementation, I can see how it handles retries, but implementing similar retry logic for structured message validation requires a fundamentally different approach than what's currently in place.

How Cryptography Handles Retries:
The encryption/decryption works at the HTTP pipeline policy level (BlobDecryptionPolicy) where:

  1. Ranges are expanded to align with encryption block boundaries BEFORE the request
  2. Each retry fetches complete encrypted blocks from the service
  3. The cipher is initialized fresh for each retry (stateless)
  4. Output is trimmed after decryption to match the original requested range

Why This Doesn't Directly Apply to Structured Messages:

  1. Different Layer: Cryptography works at the pipeline policy level (request/response interception), while structured message decoding currently happens AFTER the response in the download stream processing
  2. State Requirements: Structured messages need to track segment boundaries and validation state across retries
  3. Service Coordination: Would need the service to support segment-aligned range requests (not arbitrary byte offsets)

What Would Be Required:
To implement retry-aware structured message validation similar to cryptography, we would need to:

  1. Move structured message handling to a pipeline policy (like BlobDecryptionPolicy)
  2. Expand ranges to segment boundaries before requests
  3. Track validated segments across retries
  4. On retry, request from the next unvalidated segment boundary
  5. Maintain decoder state per segment, not per message

This is a significant architectural change that goes beyond the scope of integrating the existing decoder. I recommend either:

  • Option 1: Document that structured message validation doesn't support streaming retries (works only for complete downloads)
  • Option 2: File a separate work item to design and implement retry-aware structured message validation as a pipeline policy

Which approach would you prefer?

} else {
// No structured message processing needed, use original response
return BlobDownloadAsyncResponseConstructorProxy.create(response, onDownloadErrorResume, finalOptions);
}
});
}

Expand Down Expand Up @@ -1503,7 +1642,7 @@ Mono<Response<BlobProperties>> downloadToFileWithResponse(BlobDownloadToFileOpti
AsynchronousFileChannel channel = downloadToFileResourceSupplier(options.getFilePath(), openOptions);
return Mono.just(channel)
.flatMap(c -> this.downloadToFileImpl(c, finalRange, finalParallelTransferOptions,
options.getDownloadRetryOptions(), finalConditions, options.isRetrieveContentRangeMd5(), context))
options.getDownloadRetryOptions(), finalConditions, options.isRetrieveContentRangeMd5(), options.getContentValidationOptions(), context))
.doFinally(signalType -> this.downloadToFileCleanup(channel, options.getFilePath(), signalType));
}

Expand All @@ -1518,7 +1657,7 @@ private AsynchronousFileChannel downloadToFileResourceSupplier(String filePath,
private Mono<Response<BlobProperties>> downloadToFileImpl(AsynchronousFileChannel file, BlobRange finalRange,
com.azure.storage.common.ParallelTransferOptions finalParallelTransferOptions,
DownloadRetryOptions downloadRetryOptions, BlobRequestConditions requestConditions, boolean rangeGetContentMd5,
Context context) {
DownloadContentValidationOptions contentValidationOptions, Context context) {
// See ProgressReporter for an explanation on why this lock is necessary and why we use AtomicLong.
ProgressListener progressReceiver = finalParallelTransferOptions.getProgressListener();
ProgressReporter progressReporter
Expand All @@ -1528,8 +1667,15 @@ private Mono<Response<BlobProperties>> downloadToFileImpl(AsynchronousFileChanne
* Downloads the first chunk and gets the size of the data and etag if not specified by the user.
*/
BiFunction<BlobRange, BlobRequestConditions, Mono<BlobDownloadAsyncResponse>> downloadFunc
= (range, conditions) -> this.downloadStreamWithResponse(range, downloadRetryOptions, conditions,
rangeGetContentMd5, context);
= (range, conditions) -> {
if (contentValidationOptions != null && (contentValidationOptions.isStructuredMessageValidationEnabled() || contentValidationOptions.isMd5ValidationEnabled())) {
return this.downloadStreamWithResponse(range, downloadRetryOptions, conditions,
rangeGetContentMd5, contentValidationOptions, context);
} else {
return this.downloadStreamWithResponse(range, downloadRetryOptions, conditions,
rangeGetContentMd5, context);
}
};

return ChunkedDownloadUtils
.downloadFirstChunk(finalRange, finalParallelTransferOptions, requestConditions, downloadFunc, true,
Expand Down
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