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Unicode C

Get Object MetaData from Google Cloud Storage

See more Google Cloud Storage Examples

Demonstrates how to download a Google Cloud Storage object's metadata.

Chilkat Unicode C Downloads

Unicode C
#include <C_CkStringBuilderW.h>
#include <C_CkHttpW.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkStringBuilderW sbToken;
    HCkHttpW http;
    const wchar_t *url;
    HCkStringBuilderW sbMetaData;
    int responseCode;

    success = FALSE;

    //  This example requires the Chilkat API to have been previously unlocked.
    //  See Global Unlock Sample for sample code.

    //  This example uses a previously obtained access token having permission for the 
    //  scope "https://www.googleapis.com/auth/cloud-platform"

    //  In this example, Get Google Cloud Storage OAuth2 Access Token, 
    //  the service account access token was saved to a text file.  This example fetches the access token from the file..
    sbToken = CkStringBuilderW_Create();
    CkStringBuilderW_LoadFile(sbToken,L"qa_data/tokens/googleCloudStorageAccessToken.txt",L"utf-8");

    //  Send a GET equivalent to this curl command.

    //  curl -X GET \
    //      -H "Authorization: Bearer [OAUTH2_TOKEN]" \
    //      -o "[SAVE_TO_LOCATION]" \
    //      "https://www.googleapis.com/storage/v1/b/[BUCKET_NAME]/o/[OBJECT_NAME]?projection=full"

    http = CkHttpW_Create();

    CkHttpW_putAuthToken(http,CkStringBuilderW_getAsString(sbToken));

    //  Construct a URL to download the metadata for the object named "starfish.jpg" located in the "chilkat-ocean" bucket.
    CkHttpW_SetUrlVar(http,L"bucket_name",L"chilkat-ocean");
    CkHttpW_SetUrlVar(http,L"object_name",L"starfish.jpg");
    url = L"https://www.googleapis.com/storage/v1/b/{$bucket_name}/o/{$object_name}?projection=full";

    //  If there is an error response, then we didn't actually download the metadata,
    //  but instead we downloaded an error response..
    sbMetaData = CkStringBuilderW_Create();
    success = CkHttpW_DownloadSb(http,url,L"utf-8",sbMetaData);
    if (success == FALSE) {
        wprintf(L"%s\n",CkHttpW_lastErrorText(http));
        CkStringBuilderW_Dispose(sbToken);
        CkHttpW_Dispose(http);
        CkStringBuilderW_Dispose(sbMetaData);
        return;
    }

    responseCode = CkHttpW_getLastStatus(http);
    if (responseCode == 401) {
        wprintf(L"If invalid credentials, then it is likely the access token expired.\n");
        wprintf(L"Your app should automatically fetch a new access token and re-try.\n");
    }

    if (responseCode != 200) {
        wprintf(L"Error response code = %d\n",responseCode);
        wprintf(L"Error:\n");
        wprintf(L"%s\n",CkStringBuilderW_getAsString(sbMetaData));
        CkStringBuilderW_Dispose(sbToken);
        CkHttpW_Dispose(http);
        CkStringBuilderW_Dispose(sbMetaData);
        return;
    }

    wprintf(L"%s\n",CkStringBuilderW_getAsString(sbMetaData));
    wprintf(L"Success.\n");

    //  Sample output:

    //  {
    //   "kind": "storage#object",
    //   "id": "chilkat-ocean/starfish.jpg/1502670320090292",
    //   "selfLink": "https://www.googleapis.com/storage/v1/b/chilkat-ocean/o/starfish.jpg",
    //   "name": "starfish.jpg",
    //   "bucket": "chilkat-ocean",
    //   "generation": "1502670320090292",
    //   "metageneration": "1",
    //   "contentType": "image/jpeg",
    //   "timeCreated": "2017-08-14T00:25:20.040Z",
    //   "updated": "2017-08-14T00:25:20.040Z",
    //   "storageClass": "MULTI_REGIONAL",
    //   "timeStorageClassUpdated": "2017-08-14T00:25:20.040Z",
    //   "size": "6229",
    //   "md5Hash": "LpxZ2/JmI2fcl9/dqF2gSA==",
    //   "mediaLink": "https://www.googleapis.com/download/storage/v1/b/chilkat-ocean/o/starfish.jpg?generation=1502670320090292&alt=media",
    //   "acl": [
    //    {
    //     "kind": "storage#objectAccessControl",
    //     "id": "chilkat-ocean/starfish.jpg/1502670320090292/project-owners-933037264567",
    //     "selfLink": "https://www.googleapis.com/storage/v1/b/chilkat-ocean/o/starfish.jpg/acl/project-owners-933037264567",
    //     "bucket": "chilkat-ocean",
    //     "object": "starfish.jpg",
    //     "generation": "1502670320090292",
    //     "entity": "project-owners-933037264567",
    //     "role": "OWNER",
    //     "projectTeam": {
    //      "projectNumber": "933037264567",
    //      "team": "owners"
    //     },
    //     "etag": "CLT5kpW71dUCEAE="
    //    },
    //    {
    //     "kind": "storage#objectAccessControl",
    //     "id": "chilkat-ocean/starfish.jpg/1502670320090292/project-editors-933037264567",
    //     "selfLink": "https://www.googleapis.com/storage/v1/b/chilkat-ocean/o/starfish.jpg/acl/project-editors-933037264567",
    //     "bucket": "chilkat-ocean",
    //     "object": "starfish.jpg",
    //     "generation": "1502670320090292",
    //     "entity": "project-editors-933037264567",
    //     "role": "OWNER",
    //     "projectTeam": {
    //      "projectNumber": "933037264567",
    //      "team": "editors"
    //     },
    //     "etag": "CLT5kpW71dUCEAE="
    //    },
    //    {
    //     "kind": "storage#objectAccessControl",
    //     "id": "chilkat-ocean/starfish.jpg/1502670320090292/project-viewers-933037264567",
    //     "selfLink": "https://www.googleapis.com/storage/v1/b/chilkat-ocean/o/starfish.jpg/acl/project-viewers-933037264567",
    //     "bucket": "chilkat-ocean",
    //     "object": "starfish.jpg",
    //     "generation": "1502670320090292",
    //     "entity": "project-viewers-933037264567",
    //     "role": "READER",
    //     "projectTeam": {
    //      "projectNumber": "933037264567",
    //      "team": "viewers"
    //     },
    //     "etag": "CLT5kpW71dUCEAE="
    //    },
    //    {
    //     "kind": "storage#objectAccessControl",
    //     "id": "chilkat-ocean/starfish.jpg/1502670320090292/user-starfish@chilkat-176611.iam.gserviceaccount.com",
    //     "selfLink": "https://www.googleapis.com/storage/v1/b/chilkat-ocean/o/starfish.jpg/acl/user-starfish@chilkat-176611.iam.gserviceaccount.com",
    //     "bucket": "chilkat-ocean",
    //     "object": "starfish.jpg",
    //     "generation": "1502670320090292",
    //     "entity": "user-starfish@chilkat-176611.iam.gserviceaccount.com",
    //     "role": "OWNER",
    //     "email": "starfish@chilkat-176611.iam.gserviceaccount.com",
    //     "etag": "CLT5kpW71dUCEAE="
    //    }
    //   ],
    //   "owner": {
    //    "entity": "user-starfish@chilkat-176611.iam.gserviceaccount.com"
    //   },
    //   "crc32c": "9RjgwQ==",
    //   "etag": "CLT5kpW71dUCEAE="
    //  }
    //  


    CkStringBuilderW_Dispose(sbToken);
    CkHttpW_Dispose(http);
    CkStringBuilderW_Dispose(sbMetaData);

    }