How to escape characters in Azure Table queries? - azure

Question

I want to query for rows where a column named message starts with: metric="foo"
I tried encoding = and " with percentage and hex codes but it did not work.
Microsoft documentations says special characters must be encoded but does not tell how: https://learn.microsoft.com/en-us/rest/api/storageservices/querying-tables-and-entities#query-string-encoding
What should the query look like when value being compared contains special characters?

Answer 1

If you're using azure sdk, then the sdk already did the tricky for you.
In my test, I'm using the latest azure table storage sdk Microsoft.Azure.Cosmos.Table, version 1.0.4.
The test code:
static void Main(string[] args)
{
string connstr = "xxxx";
var storageAccount = CloudStorageAccount.Parse(connstr);
CloudTableClient tableClient = storageAccount.CreateCloudTableClient();
CloudTable table = tableClient.GetTableReference("myCustomer123");
TableQuery<CustomerEntity> query = new TableQuery<CustomerEntity>();
string myfilter = TableQuery.CombineFilters(TableQuery.GenerateFilterCondition("PartitionKey", QueryComparisons.Equal, "ivan"),
TableOperators.And,
//for metric="foo", like below.
TableQuery.GenerateFilterCondition("PhoneNumber", QueryComparisons.Equal, "metric=\"foo\"")
);
query.FilterString = myfilter;
var items = table.ExecuteQuery(query);
foreach (var item in items)
{
Console.WriteLine(item.RowKey);
Console.WriteLine(item.PhoneNumber);
}
Console.WriteLine("*****end******");
Console.ReadLine();
}
Test result:

Answer 2

If you want to use the parameter to filter results, you can use ?$filter=<your parameter>%20eq%20'<vaule>'. For example
var date = DateTime.Now.ToUniversalTime().AddYears(1).ToString("R");
var CanonicalizedResource = "/" + StorageAccountName + "/people";
var StringToSign = date + "\n" + CanonicalizedResource;
// List the containers in a storage account.
// ListContainersAsyncREST(StorageAccountName, StorageAccountKey, CancellationToken.None).GetAwaiter().GetResult();
var hmacsha = new HMACSHA256();
hmacsha.Key = Convert.FromBase64String(StorageAccountKey);
var sig= hmacsha.ComputeHash(UTF8Encoding.UTF8.GetBytes(StringToSign));
var sig1 = Convert.ToBase64String(sig);
Console.WriteLine(sig1);
String uri = "https://jimtestperfdiag516.table.core.windows.net/people" + "?$filter=PartitionKey%20eq%20'Jim'";
HttpClient client = new HttpClient();
var httpRequestMessage = new HttpRequestMessage(HttpMethod.Get, uri);
httpRequestMessage.Headers.Add("x-ms-date", date);
var str = "SharedKeyLite " + StorageAccountName + ":" + sig1;
httpRequestMessage.Headers.TryAddWithoutValidation("Authorization", str);
httpRequestMessage.Headers.Add("x-ms-version", "2017-04-17");
httpRequestMessage.Headers.Add("Accept", "application/json;odata=fullmetadata");
var results = client.SendAsync(httpRequestMessage).Result;
var response = results.Content.ReadAsStringAsync().Result;
var objs = JsonConvert.DeserializeObject(response);
Console.WriteLine(objs);