Utility class to fetch the latest version of a segmented object. More...
#include <segment-fetcher.hpp>
Classes | |
class | Options |
Public Types | |
typedef function< void(ConstBufferPtr data)> | CompleteCallback |
typedef function< void(uint32_t code, const std::string &msg)> | ErrorCallback |
enum | ErrorCode { INTEREST_TIMEOUT = 1, DATA_HAS_NO_SEGMENT = 2, SEGMENT_VALIDATION_FAIL = 3, NACK_ERROR = 4, FINALBLOCKID_NOT_SEGMENT = 5 } |
Error codes passed to onError More... | |
Static Public Member Functions | |
static shared_ptr< SegmentFetcher > | fetch (Face &face, const Interest &baseInterest, security::v2::Validator &validator, const CompleteCallback &completeCallback, const ErrorCallback &errorCallback) |
Initiates segment fetching. More... | |
static shared_ptr< SegmentFetcher > | fetch (Face &face, const Interest &baseInterest, shared_ptr< security::v2::Validator > validator, const CompleteCallback &completeCallback, const ErrorCallback &errorCallback) |
Initiate segment fetching. More... | |
static shared_ptr< SegmentFetcher > | start (Face &face, const Interest &baseInterest, security::v2::Validator &validator, const Options &options=Options()) |
Initiates segment fetching. More... | |
Public Attributes | |
Signal< SegmentFetcher > | afterSegmentNacked |
Emits whenever an Interest for a data segment is nacked. More... | |
Signal< SegmentFetcher, Data > | afterSegmentReceived |
Emits whenever a data segment received. More... | |
Signal< SegmentFetcher > | afterSegmentTimedOut |
Emits whenever an Interest for a data segment times out. More... | |
Signal< SegmentFetcher, Data > | afterSegmentValidated |
Emits whenever a received data segment has been successfully validated. More... | |
Signal< SegmentFetcher, ConstBufferPtr > | onComplete |
Emits upon successful retrieval of the complete data. More... | |
Signal< SegmentFetcher, uint32_t, std::string > | onError |
Emits when the retrieval could not be completed due to an error. More... | |
Utility class to fetch the latest version of a segmented object.
SegmentFetcher assumes that segments in the object are named /<prefix>/<version>/<segment>
, where:
<prefix>
is the specified prefix,<version>
is an unknown version that needs to be discovered, and<segment>
is a segment number (The number of segments in the object is unknown until a Data packet containing the FinalBlockId
field is receieved.)The following logic is implemented in SegmentFetcher:
Interest:
/<prefix>?ndn.CanBePrefix=true&ndn.MustBeFresh=true
<version> = Data.getName().get(-2)
Interest:
/<prefix>/<version>/<segment=(N)>
onComplete
with a memory block that combines the content of all segments in the object.If an error occurs during the fetching process, onError
is signaled with one of the error codes from SegmentFetcher::ErrorCode
.
A Validator instance must be specified to validate individual segments. Every time a segment has been successfully validated, afterValidationSuccess
will be signaled. If a segment fails validation, afterValidationFailure
will be signaled.
Examples:
Definition at line 102 of file segment-fetcher.hpp.
typedef function<void (ConstBufferPtr data)> ndn::util::SegmentFetcher::CompleteCallback |
Definition at line 106 of file segment-fetcher.hpp.
typedef function<void (uint32_t code, const std::string& msg)> ndn::util::SegmentFetcher::ErrorCallback |
Definition at line 107 of file segment-fetcher.hpp.
Error codes passed to onError
Enumerator | |
---|---|
INTEREST_TIMEOUT |
retrieval timed out because the maximum timeout between the successful receipt of segments was exceeded |
DATA_HAS_NO_SEGMENT |
one of the retrieved Data packets lacked a segment number in the last Name component (excl. implicit digest) |
SEGMENT_VALIDATION_FAIL |
one of the retrieved segments failed user-provided validation |
NACK_ERROR |
an unrecoverable Nack was received during retrieval |
FINALBLOCKID_NOT_SEGMENT |
a received FinalBlockId did not contain a segment component |
Definition at line 112 of file segment-fetcher.hpp.
|
static |
Initiates segment fetching.
start
face | Reference to the Face that should be used to fetch data |
baseInterest | An Interest for the initial segment of requested data. This interest may include a custom InterestLifetime and parameters that will propagate to all subsequent Interests. The only exception is that the initial Interest will be forced to include the parameters "CanBePrefix=true" and "MustBeFresh=true", which will be turned off in subsequent Interests. |
validator | Reference to the Validator that should be used to validate data. Caller must ensure validator is valid until either completeCallback or errorCallback is invoked. |
completeCallback | Callback to be fired when all segments are fetched |
errorCallback | Callback to be fired when an error occurs ( |
Definition at line 97 of file segment-fetcher.cpp.
|
static |
Initiate segment fetching.
start
face | Reference to the Face that should be used to fetch data |
baseInterest | An Interest for the initial segment of requested data. This interest may include a custom InterestLifetime and parameters that will propagate to all subsequent Interests. The only exception is that the initial Interest will be forced to include the parameters "CanBePrefix=true" and "MustBeFresh=true", which will both be set to false in subsequent Interests. |
validator | A shared_ptr to the Validator that should be used to validate data. |
completeCallback | Callback to be fired when all segments are fetched |
errorCallback | Callback to be fired when an error occurs ( |
Definition at line 115 of file segment-fetcher.cpp.
|
static |
Initiates segment fetching.
face | Reference to the Face that should be used to fetch data |
baseInterest | Interest for the initial segment of requested data. This interest may include a custom InterestLifetime and parameters that will propagate to all subsequent Interests. The only exception is that the initial Interest will be forced to include the "CanBePrefix=true" and "MustBeFresh=true" parameters, which will not be included in subsequent Interests. |
validator | Reference to the Validator the fetcher will use to validate data. The caller must ensure the validator is valid until either onComplete or onError has been signaled. |
options | Options controlling the transfer |
Transfer completion, failure, and progress are indicated via signals.
Definition at line 86 of file segment-fetcher.cpp.
Signal<SegmentFetcher> ndn::util::SegmentFetcher::afterSegmentNacked |
Emits whenever an Interest for a data segment is nacked.
Definition at line 332 of file segment-fetcher.hpp.
Signal<SegmentFetcher, Data> ndn::util::SegmentFetcher::afterSegmentReceived |
Emits whenever a data segment received.
Definition at line 322 of file segment-fetcher.hpp.
Signal<SegmentFetcher> ndn::util::SegmentFetcher::afterSegmentTimedOut |
Emits whenever an Interest for a data segment times out.
Definition at line 337 of file segment-fetcher.hpp.
Signal<SegmentFetcher, Data> ndn::util::SegmentFetcher::afterSegmentValidated |
Emits whenever a received data segment has been successfully validated.
Definition at line 327 of file segment-fetcher.hpp.
Signal<SegmentFetcher, ConstBufferPtr> ndn::util::SegmentFetcher::onComplete |
Emits upon successful retrieval of the complete data.
Definition at line 310 of file segment-fetcher.hpp.
Signal<SegmentFetcher, uint32_t, std::string> ndn::util::SegmentFetcher::onError |
Emits when the retrieval could not be completed due to an error.
Handler(s) are provided with an error code and a string error message.
Definition at line 317 of file segment-fetcher.hpp.