This article is about sending SMS using ASP.NET through HTTP.
It is intended for web developers with a basic knowledge of the
ASP.NET technology. The reader should be familiar with Microsoft Visual Studio
and the C# programming language. The page contains a downloadable source code
(see above), a list of aims you can achieve using the code, a list of
prerequisites, a description and depiction of the architecture and operation
of the system, step-by-step instructions about how to use the code and a
detailed interpretation.
It also includes a brief summary, answers to frequently asked questions, as well
as links to related information.
When to use this code
This code is particularly useful for those who wish to
add SMS functionality to a website.
add SMS functionality to a corporate Intranet.
create automated SMS notifications.
increase website security by adding SMS login.
Prerequisites
The following table lists the software requirements of the
system.
Note that you can download Ozeki NG - SMS Gateway and .NET Framework 3.5
on the download page.
Operating system:
Windows 2012 R2, Windows 2016, Windows 2019 Windows 8 or Windows 10
Other software requirements:
Internet Information Services (IIS)
.NET Framework 3.5
Ozeki NG-SMS gateway
Development platform:
Microsoft Visual Studio .NET
How it works
To send SMS messages from ASP.NET applications, you need to
install
Ozeki NG SMS Gateway on your computer. Ozeki NG - SMS Gateway will use a
GSM phone/modem attached to your PC
(with a phone-to-PC data cable) or an
IP SMS connection
to send messages. Your ASP.NET application will perform an HTTP request
to send messages using the Ozeki NG program. For a better understanding of how
it works, please look at the following diagram (Figure 1).
Figure 1 - Sending SMS from an ASP.NET application
In the diagram you can see an Internet user, a web server
with the ASP.NET application, Ozeki NG - SMS Gateway, a mobile phone attached
to the server computer and mobile user receiving the message.
Wherever the Internet user is, if they know the IP address or URL
of the computer running the ASP script, and if they are authorized to log in,
they can compose and send messages to any recipients.
After the Internet user's action, the ASP.NET application initiates
the process by posting an SMS message to the built-in web server of
Ozeki NG - SMS Gateway. Ozeki NG will forward the message to the GSM network
through a mobile phone attached to the PC using a data cable, and
the mobile user will receive the SMS message.
Using the code
To use the downloaded ASP code, follow these steps:
Step 1:
Unpack the downloaded zip file.
Step 2:
Copy the smssend.aspx and smssend.aspx.cs files into the "C:\Inetpub\wwwroot\" directory
(the main directory of the IIS Server).
Picture help
Step 3:
Set/Change the fixed data in the smssend.aspx.cs file (e.g., ozSURL, ozSPort, ozUser, ozPassw).
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Step 4:
Start the Ozeki NG - SMS Gateway Server (if not running).
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Step 5:
Start a web browser application (IE, Firefox, etc.) and enter this: http://127.0.0.1/smssend.aspx
(127.0.0.1 means that the smssend.aspx and smssend.aspx.cs files reside on the same computer
on which the browser has been opened).
Picture help
Step 6:
Fill in the necessary fields, and then click the "Send" button.
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Step 7:
Verify the message being sent in the Ozeki NG - SMS Gateway Server.
Picture help
Understanding the code
The downloadable sample script tells Ozeki NG - SMS Gateway Server to send an
SMS message to the given phone number with the given content. Inside the script you have to
set the URL of the Ozeki NG Server with the port number, the username (specifying
who can log in to the Ozeki NG Server) with the password and the type of the
SMS message.
The source code of the example application is structured in the following way:
smssend.aspx:
In this file there are page builder asp elements (text
boxes, labels, etc.).
smssend.aspx.cs:
Page_Load(...): does some basic settings.
buttonSendOnClick(...): creates and sends the sms from
the given data.
Description of the process depicted in Figure 1 above:
Step 1:Create the HTML
form
In the smssend.aspx file, you create the form that requests the sms data.
The Internet user fills in the necessaries.
Label and textbox pairs will be displayed. Labels identify the requested data
for the Internet user,
and they will type it in textboxes. The user will be asked to fill in the
Recipient and Message text fields.
A multiline textbox is used to inform the Internet user about error(s) or
result(s)
of sending the message. At first, the error box will be
invisible (it will be set in the smssend.aspx.cs file).
In the "protected void Page_Load(object sender, EventArgs e)" procedure
(in smssend.aspx.cs), you set the width of textboxes and the
error box height in rows. The text of the error box is red, and the first is
invisible and empty. If 'using the net browser' the page is
downloaded for the first time, fill in the recipient and message boxes with
predefined texts.
After filling in the fields and clicking the Send button , the ASP
server receives the information about the form.
In the smssend.aspx.cs file, the "protected void buttonSendOnClick(object
sender, EventArgs e)" procedure is called.
At the beginning of the procedure, check the data of the textbox fields.
The Recipient box is mandatory.
If it is empty, the processing will be aborted, and the Internet user will be
shown the error. If the checking is successful, you will create the URL that
will tell the Ozeki NG - SMS Gateway Server the requested information. We need
the following: the URL of the computer running Ozeki NG - SMS Gateway Server
the default URL is http://127.0.0.1/httpapi
(127.0.0.1 means that Ozeki NG - SMS Gateway Server is installed on the same
computer on which the ASP.NET script is running), the port number on which the
server listens, the username, which is authorized to log in to the Ozeki
NG - SMS Gateway Server and to send messages
(the default username is admin), the user's password (the default is abc123),
the message type (the default is SMS:TEXT), the recipient and the message data.
The following values must be URL-encoded: username,
password, recipient and message data.
smssend.aspx.cs
...
protected void buttonSendOnClick(object sender, EventArgs e)
{
//fields are required to be filled in:
if (textboxRecipient.Text == "")
{
textboxError.Text += "Recipient(s) field must not be empty!\n";
textboxError.Visible = true;
return;
}
//we are creating the necessary URL string:
string ozSURL = "http://127.0.0.1"; //where Ozeki NG SMS Gateway is running
string ozSPort = "9501"; //port number where Ozeki NG SMS Gateway is listening
string ozUser = HttpUtility.UrlEncode("admin"); //username for successful login
string ozPassw = HttpUtility.UrlEncode("abc123"); //user's password
string ozMessageType = "SMS:TEXT"; //type of message
string ozRecipients = HttpUtility.UrlEncode(textboxRecipient.Text); //who
will get the message
string ozMessageData = HttpUtility.UrlEncode(textboxMessage.Text); //body
of message
string createdURL = ozSURL + ":" + ozSPort + "/httpapi" +
"?action=sendMessage" +
"&username=" + ozUser +
"&password=" + ozPassw +
"&messageType=" + ozMessageType +
"&recipient=" + ozRecipients +
"&messageData=" + ozMessageData;
...
}
...
Step 3:Sending a request to the SMS Gateway and receiving the answer In the code you send a request to the Ozeki NG - SMS Gateway Server with
the data of the message.
It will create an SMS and send it to
the recipient (mobile user) using a GSM modem/phone (if the given data is correct)
and send you the result.
You create a request to the Ozeki NG - SMS Gateway Server at the URL
created above.
When it is done, you will receive a response from the Ozeki NG - SMS Gateway
Server.
The information will be retrieved from it and shown to the Internet user.
Whatever problem you have, it is because the Ozeki NG - SMS Gateway Server
is not running at the moment of sending data.
smssend.aspx.cs
...
protected void buttonSendOnClick(object sender, EventArgs e)
{
...
try
{
//Create the request and send data to Ozeki NG SMS Gateway Server by
HTTP connection
HttpWebRequest myReq = (HttpWebRequest)WebRequest.Create(createdURL);
//Get response from Ozeki NG SMS Gateway Server and read the answer
HttpWebResponse myResp = (HttpWebResponse)myReq.GetResponse();
System.IO.StreamReader respStreamReader = new System.IO.StreamReader(myResp.GetResponseStream());
string responseString = respStreamReader.ReadToEnd();
respStreamReader.Close();
myResp.Close();
//inform the user
textboxError.Text = responseString;
textboxError.Visible = true;
}
catch (Exception)
{
//if sending request or getting response is not successful, Ozeki NG - SMS Gateway Server may not be running
textboxError.Text = "Ozeki NG SMS Gateway Server is not running!";
textboxError.Visible = true;
}
}
...
Summary
In the article it has been explained how you can add SMS functionality to your
website by using the downloadable ASP.NET example code. You can freely use and
modify that script. Using ASP.NET scripts (and the Ozeki NG - SMS Gateway
Server) you can create a lot
of useful services(e.g.: you can add SMS functionality to a website or a
corporate Intranet, create automated SMS notifications, increase website security
by adding SMS login, etc.).
Frequently asked questions
Question: How can I send the same message to different phone numbers?
Answer: Separate the phone numbers with the comma character (,).
For example:
action can be: signal-high, signal-medium, signal-low, signal-none, signal-delete
Question: Can I run the ASP script on a computer different
from the one running the Ozeki NG - SMS Gateway Server?
Answer: Yes, you can. In the script you have to set the URL and the
port number of the computer running the Ozeki NG - SMS Gateway Server.
Question: Can I set the phone number so that
the recipient can see where the sms comes from?
Answer: Yes, you can. In the script you have to set an originator field and
include it in the URL string you have created. It works
only if you have IP SMS connection.
...
protected void buttonSendOnClick(object sender, EventArgs e)
{
...
//we creating the necessary URL string:
string ozSURL = "http://127.0.0.1"; //where Ozeki NG SMS Gateway is running
string ozSPort = "9501"; //port number where Ozeki NG SMS Gateway is listening
string ozUser = HttpUtility.UrlEncode("admin"); //username for successful login
string ozPassw = HttpUtility.UrlEncode("abc123"); //user's password
string ozOriginator = HttpUtility.UrlEncode("+449998887");//originator of the message
string ozMessageType = "SMS:TEXT"; //type of message
string ozRecipients = HttpUtility.UrlEncode(textboxRecipient.Text); //who will get the message
string ozMessageData = HttpUtility.UrlEncode(textboxMessage.Text); //body of message
string createdURL = ozSURL + ":" + ozSPort + "/httpapi" +
"?action=sendMessage" +
"&username=" + ozUser +
"&password=" + ozPassw +
"&originator=" + ozOriginator +
"&messageType=" + ozMessageType +
"&recipient=" + ozRecipients +
"&messageData=" + ozMessageData;
...
}
...