(C#) BatchModify - Add a Label to each Message in Search Results

Searchs GMail for messages meeting a criteria and adds a label to each message found.

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

bool success;

Chilkat.Http http = new Chilkat.Http();
http.AuthToken = "GMAIL-ACCESS-TOKEN";

string userId = "me";
http.SetUrlVar("userId",userId);

string query = "subject:questions";
http.SetUrlVar("query",query);

string url = "https://www.googleapis.com/gmail/v1/users/{$userId}/messages?q={$query}";

Chilkat.StringBuilder sb = new Chilkat.StringBuilder();
success = http.QuickGetSb(url,sb);
if (success != true) {
    Debug.WriteLine(http.LastErrorText);
    return;
}

Chilkat.JsonObject json = new Chilkat.JsonObject();
json.LoadSb(sb);
json.EmitCompact = false;
Debug.WriteLine(json.Emit());

if (http.LastStatus != 200) {
    Debug.WriteLine("Failed.");
    return;
}

// If successful, the received JSON looks like this:
// {
//   "messages": [
//     {
//       "id": "166f583051d36144",
//       "threadId": "166f583051d36144"
//     },
//     {
//       "id": "166f5815e1f36144",
//       "threadId": "166f5815e1f36144"
//     },
// 	...
//     {
//       "id": "166f580639e36144",
//       "threadId": "166f580639e36144"
//     },
//     {
//       "id": "15dbc2e28ec789c6",
//       "threadId": "15dbc2e28ec789c6"
//     }
//   ],
//   "nextPageToken": "13434766102274844688",
//   "resultSizeEstimate": 103
// }
// 

// Next, we'll be sending an HTTP POST to add the label "questions" to each message in the
// search results.  The JSON to be sent for the batchModify is this:

// 	{
// 	  "ids": [
// 	    string
// 	  ],
// 	  "addLabelIds": [
// 	    string
// 	  ],
// 	  "removeLabelIds": [
// 	    string
// 	  ]
// 	}

// We'll omit "removeLabelIds" because we're not removing any labels.
// We are parsing the JSON search results, and at the same time building the batchModify JSON.

Chilkat.JsonObject json2 = new Chilkat.JsonObject();

int i = 0;
int numMessages = json.SizeOfArray("messages");
while ((i < numMessages)) {
    json.I = i;
    string id = json.StringOf("messages[i].id");
    json2.I = i;
    json2.UpdateString("ids[i]",id);
    i = i + 1;
}

// We need the id of the label (not the name).
// I know the name of the label is "questions", but I need to know the id.
// See this example: Get Label Id by Name
// The id of my label named "questions" is "Label_43"
string labelId = "Label_43";
json2.UpdateString("addLabelIds[0]",labelId);
json2.UpdateNewArray("removeLabelIds");

json2.EmitCompact = false;
Debug.WriteLine(json2.Emit());

// Send the batchModify
url = "https://www.googleapis.com/gmail/v1/users/{$userId}/messages/batchModify";
Chilkat.HttpResponse resp = http.PostJson3(url,"application/json",json2);
if (http.LastMethodSuccess != true) {
    Debug.WriteLine(http.LastErrorText);
    return;
}

Debug.WriteLine("status = " + Convert.ToString(resp.StatusCode));

// A 204 response status indicate success.
if (resp.StatusCode != 204) {
    Debug.WriteLine(resp.BodyStr);
    Debug.WriteLine("Failed.");

    return;
}

// The 204 response has an empty response body..

Debug.WriteLine("BatchModify success!");