Querying Assets (C/C++)
Available APIs
For details about the API, see:
int32_t OH_Asset_Query(const Asset_Attr *query, uint32_t queryCnt, Asset_ResultSet *resultSet)
The following table describes the parameters.
Attribute Name (Asset_Tag) | Attribute Content (Asset_Value) | Mandatory | Description |
---|---|---|---|
ASSET_TAG_ALIAS | Type: uint8[] Length: 1-256 bytes |
No | Asset alias, which uniquely identifies an asset. |
ASSET_TAG_ACCESSIBILITY | Type: uint32_t Value range: see Asset_Accessibility |
No | Access control based on the lock screen status. |
ASSET_TAG_REQUIRE_PASSWORD_SET | Type: bool | No | Whether the asset is accessible only when a lock screen password is set. |
ASSET_TAG_AUTH_TYPE | Type: uint32_t Value range: see Asset_AuthType |
No | Type of user authentication required for accessing the asset. |
ASSET_TAG_SYNC_TYPE | Type: uint32_t Value range: see Asset_SyncType |
No | Type of sync supported by the asset. |
ASSET_TAG_IS_PERSISTENT | Type: bool | No | Whether to retain the asset when the application is uninstalled. |
ASSET_TAG_DATA_LABEL_CRITICAL_1 | Type: uint8[] Length: 1-512 bytes |
No | Additional asset data customized by the service with integrity protection. |
ASSET_TAG_DATA_LABEL_CRITICAL_2 | Type: uint8[] Length: 1-512 bytes |
No | Additional asset data customized by the service with integrity protection. |
ASSET_TAG_DATA_LABEL_CRITICAL_3 | Type: uint8[] Length: 1-512 bytes |
No | Additional asset data customized by the service with integrity protection. |
ASSET_TAG_DATA_LABEL_CRITICAL_4 | Type: uint8[] Length: 1-512 bytes |
No | Additional asset data customized by the service with integrity protection. |
ASSET_TAG_DATA_LABEL_NORMAL_1 | Type: uint8[] Length: 1-512 bytes |
No | Additional asset data customized by the service without integrity protection. |
ASSET_TAG_DATA_LABEL_NORMAL_2 | Type: uint8[] Length: 1-512 bytes |
No | Additional asset data customized by the service without integrity protection. |
ASSET_TAG_DATA_LABEL_NORMAL_3 | Type: uint8[] Length: 1-512 bytes |
No | Additional asset data customized by the service without integrity protection. |
ASSET_TAG_DATA_LABEL_NORMAL_4 | Type: uint8[] Length: 1-512 bytes |
No | Additional asset data customized by the service without integrity protection. |
ASSET_TAG_RETURN_TYPE | Type: uint32_t Value range: see Asset_ReturnType |
No | Type of the asset query result to return. |
ASSET_TAG_RETURN_LIMIT | Type: uint32_t | No | Maximum number of asset records to return. |
ASSET_TAG_RETURN_OFFSET | Type: uint32_t Value range: 1-65536 |
No | Offset of the asset query result. NOTE: This parameter specifies the starting asset record to return in batch asset query. |
ASSET_TAG_RETURN_ORDERED_BY | Type: uint32_t Value: ASSET_TAG_DATA_LABEL_xxx |
No | How the query results are sorted. Currently, the results can be sorted only by ASSET_TAG_DATA_LABEL. NOTE: By default, assets are returned in the order in which they are added. |
Example
Querying the Plaintext of an Asset
Query the plaintext of asset demo_alias.
-
Add the dynamic library in the CMake script.
target_link_libraries(entry PUBLIC libasset_ndk.z.so)
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Add an asset.
#include <string.h> #include "asset/asset_api.h" void QueryAsset() { static const char *ALIAS = "demo_alias"; Asset_Blob alias = { (uint32_t)(strlen(ALIAS)), (uint8_t *)ALIAS }; Asset_Attr attr[] = { { .tag = ASSET_TAG_ALIAS, .value.blob = alias }, // Specify the alias of the asset to query. { .tag = ASSET_TAG_RETURN_TYPE, .value.u32 = ASSET_RETURN_ALL }, // Return all asset information, including the attributes and asset plaintext. }; Asset_ResultSet resultSet = {0}; int32_t ret = OH_Asset_Query(attr, sizeof(attr) / sizeof(attr[0]), &resultSet); if (ret == ASSET_SUCCESS) { // Parse the resultSet. for (uint32_t i = 0; i < resultSet.count; i++) { // Parse the secret: the data is secret->blob.data, the size is secret->blob.size. Asset_Attr *secret = OH_Asset_ParseAttr(resultSet.results + i, ASSET_TAG_SECRET); } } OH_Asset_FreeResultSet(&resultSet); }
Querying Attributes of an Asset
Query attributes of asset demo_alias.
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Add the dynamic library in the CMake script.
target_link_libraries(entry PUBLIC libasset_ndk.z.so)
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Add an asset.
#include <string.h> #include "asset/asset_api.h" void QueryAttributes() { static const char *ALIAS = "demo_alias"; Asset_Blob alias = { (uint32_t)(strlen(ALIAS)), (uint8_t *)ALIAS }; Asset_Attr attr[] = { { .tag = ASSET_TAG_ALIAS, .value.blob = alias }, // Specify the alias of the asset to query. { .tag = ASSET_TAG_RETURN_TYPE, .value.u32 = ASSET_RETURN_ATTRIBUTES }, // Return only the asset attributes, that is, the result does not include the asset plaintext. }; Asset_ResultSet resultSet = {0}; int32_t ret = OH_Asset_Query(attr, sizeof(attr) / sizeof(attr[0]), &resultSet); if (ret == ASSET_SUCCESS) { // Parse the result. for (uint32_t i = 0; i < resultSet.count; i++) { // Parse the data label: the data is label->blob.data, the size is label->blob.size. Asset_Attr *label = OH_Asset_ParseAttr(resultSet.results + i, ASSET_TAG_DATA_LABEL_NORMAL_1); } } OH_Asset_FreeResultSet(&resultSet); }
Querying Attributes of Assets
Query attributes of assets with the tag of demo_label and return a total of 10 records sorted by DATA_LABEL_NORMAL_1 starting from the fifth record that matches the search criteria.
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Add the dynamic library in the CMake script.
target_link_libraries(entry PUBLIC libasset_ndk.z.so)
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Add an asset.
#include <string.h> #include "asset/asset_api.h" void BatchQuery() { static const char *LABEL = "demo_label"; Asset_Blob label = { (uint32_t)(strlen(LABEL)), (uint8_t *)LABEL }; Asset_Attr attr[] = { { .tag = ASSET_TAG_RETURN_TYPE, .value.u32 = ASSET_RETURN_ATTRIBUTES }, { .tag = ASSET_TAG_DATA_LABEL_NORMAL_1, .value.blob = label }, { .tag = ASSET_TAG_RETURN_OFFSET, .value.u32 = 5 }, { .tag = ASSET_TAG_RETURN_LIMIT, .value.u32 = 10 }, { .tag = ASSET_TAG_RETURN_ORDERED_BY, .value.u32 = ASSET_TAG_DATA_LABEL_NORMAL_1 }, }; Asset_ResultSet resultSet = { 0 }; int32_t ret = OH_Asset_Query(attr, sizeof(attr) / sizeof(attr[0]), &resultSet); if (ret == ASSET_SUCCESS) { // Parse the result. for (uint32_t i = 0; i < resultSet.count; i++) { // Parse the data alias: the data is alias->blob.data, the size is alias->blob.size. Asset_Attr *alias = OH_Asset_ParseAttr(resultSet.results + i, ASSET_TAG_ALIAS); } } OH_Asset_FreeResultSet(&resultSet); }
Constraints
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Batch asset query
The assets queried are transmitted to the service through an IPC channel. Due to the limitation of the IPC buffer size, the maximum number of assets to be queried at a time cannot exceed 40.