### Get URI Parameter Value

Source: https://github.com/azure/api-management-policy-snippets/blob/master/policy-expressions/README.md

Retrieves the value of a URI parameter. If the parameter is not found, it returns an optional default value.

```csharp
context.Request.MatchedParameters.GetValueOrDefault("parameter-name","optional-default-value")
```

--------------------------------

### Get HTTP Header Value

Source: https://github.com/azure/api-management-policy-snippets/blob/master/policy-expressions/README.md

Retrieves the value of a specified HTTP header. If the header is not found, it returns an optional default value.

```csharp
context.Request.Headers.GetValueOrDefault("header-name","optional-default-value")
```

--------------------------------

### Get Policy Variable

Source: https://github.com/azure/api-management-policy-snippets/blob/master/policy-expressions/README.md

Retrieves the value of a policy variable, assuming it is a string. If the variable is not found, it returns an optional default value.

```csharp
context.Variables.GetValueOrDefault<string>("variable-name","optional-default-value")
```

--------------------------------

### Get Query String Parameter Value

Source: https://github.com/azure/api-management-policy-snippets/blob/master/policy-expressions/README.md

Retrieves the value of a query string parameter. If the parameter is not found, it returns an optional default value.

```csharp
context.Request.Url.Query.GetValueOrDefault("parameter-name", "optional-default-value")
```

--------------------------------

### Get Value from JSON Response Variable

Source: https://github.com/azure/api-management-policy-snippets/blob/master/policy-expressions/README.md

Extracts a value from the JSON body of a response stored in a policy variable using a JSONPath expression.

```csharp
(string)((IResponse)context.Variables["response-variable-name"]).Body.As<JObject>().SelectToken("root.child jsonpath")
```

--------------------------------

### Get Value from JSON Body

Source: https://github.com/azure/api-management-policy-snippets/blob/master/policy-expressions/README.md

Extracts a value from the request's JSON body using a JSONPath expression. The preserveContent option ensures the body can be read again.

```csharp
(string)context.Request.Body.As<JObject>(preserveContent: true).SelectToken("root.child jsonpath")
```

--------------------------------

### Check Client Certificate Existence

Source: https://github.com/azure/api-management-policy-snippets/blob/master/policy-expressions/README.md

Verifies if a client certificate is present in the request.

```csharp
context.Request.Certificate != null
```

--------------------------------

### Verify Client Certificate Validity (with revocation check)

Source: https://github.com/azure/api-management-policy-snippets/blob/master/policy-expressions/README.md

Checks if the client certificate is valid, including a check against the certificate revocation list.

```csharp
context.Request.Certificate.Verify() == true
```

--------------------------------

### Check Client Certificate Thumbprint

Source: https://github.com/azure/api-management-policy-snippets/blob/master/policy-expressions/README.md

Verifies if the client certificate's thumbprint matches a specified uppercase string.

```csharp
context.Request.Certificate.Thumbprint == "EXPECTED-THUMBPRINT-IN-UPPER-CASE"
```

--------------------------------

### Verify Client Certificate Validity (without revocation check)

Source: https://github.com/azure/api-management-policy-snippets/blob/master/policy-expressions/README.md

Checks if the client certificate is valid, bypassing the certificate revocation list check.

```csharp
context.Request.Certificate.VerifyNoRevocation() == true
```

--------------------------------

### OAuth Proxy Sign-in Policy

Source: https://github.com/azure/api-management-policy-snippets/blob/master/examples/oauth-proxy/readme.md

This policy initiates a front-channel code/PKCE flow with an Identity Provider. Configure it as the 'signin' operation within an API called 'OAuth'.

```xml
<policies>
    <inbound>
        <base />
        <!-- Sign-in policy -->
        <oauth-proxy-sign-in />
    </inbound>
</policies>
```

--------------------------------

### Generate Base64 Random Bytes in .NET

Source: https://github.com/azure/api-management-policy-snippets/blob/master/examples/oauth-proxy/readme.md

Use this .NET code to generate Base 64 encoded random bytes for encryption keys.

```csharp
Convert.ToBase64String(RandomNumberGenerator.GetBytes(<size>))
```

--------------------------------

### Check Client Certificate Issuer

Source: https://github.com/azure/api-management-policy-snippets/blob/master/policy-expressions/README.md

Verifies if the client certificate's issuer matches a specified string.

```csharp
context.Request.Certificate.Issuer == "trusted-issuer"
```

--------------------------------

### Check URI Parameter Value

Source: https://github.com/azure/api-management-policy-snippets/blob/master/policy-expressions/README.md

Compares the value of a URI parameter against an expected string, ignoring case. Returns true if they match or if the parameter is not present and the default empty string matches.

```csharp
context.Request.MatchedParameters.GetValueOrDefault("parameter-name", "").Equals("expected-value", StringComparison.OrdinalIgnoreCase) == true
```

--------------------------------

### Protect Web Applications with OAuth Proxy Policies

Source: https://github.com/azure/api-management-policy-snippets/blob/master/examples/oauth-proxy/readme.md

This XML snippet outlines the inbound, backend, outbound, and error handling policies for an OAuth proxy. It includes fragments for token endpoint, session management, and token validation.

```xml
<policies>
    <inbound>
        <include-fragment fragment-id="oauth-proxy-token-endpoint-fragment" />
        <include-fragment fragment-id="oauth-proxy-session-fragment" />
        <include-fragment fragment-id="oauth-proxy-validate-token-fragment" />
        
        <!-- Adds the following headers to the downstream request: 
            
            Authorization: Bearer {access-token}
            x-proxy-id-token: {id-token} 
            x-proxy-id-token-name: {id-token name claim}
            x-proxy-id-token-preferred-username: {id-token preferred-username claim} 
            -->
        <base />
    </inbound>
    <backend>
        <base />
    </backend>
    <outbound>
        <include-fragment fragment-id="oauth-proxy-slide-session-fragment" />
        <base />
    </outbound>
    <on-error>
        <include-fragment fragment-id="oauth-proxy-slide-session-fragment" />
        <base />
    </on-error>
</policies>
```

--------------------------------

### Check Client Certificate Subject

Source: https://github.com/azure/api-management-policy-snippets/blob/master/policy-expressions/README.md

Verifies if the client certificate's subject name matches a specified string.

```csharp
context.Request.Certificate.SubjectName.Name == "expected-subject-name"
```

--------------------------------

### Check Policy Variable Existence

Source: https://github.com/azure/api-management-policy-snippets/blob/master/policy-expressions/README.md

Verifies if a specific policy variable exists.

```csharp
context.Variables.ContainsKey("variable-name") == true
```

--------------------------------

### Check Query String Parameter Value

Source: https://github.com/azure/api-management-policy-snippets/blob/master/policy-expressions/README.md

Compares the value of a query string parameter against an expected string, ignoring case. Returns true if they match or if the parameter is not present and the default empty string matches.

```csharp
context.Request.Url.Query.GetValueOrDefault("parameter-name", "").Equals("expected-value", StringComparison.OrdinalIgnoreCase) == true
```

--------------------------------

### Check HTTP Header Value

Source: https://github.com/azure/api-management-policy-snippets/blob/master/policy-expressions/README.md

Compares the value of an HTTP header against an expected string, ignoring case. Returns true if they match or if the header is not present and the default empty string matches.

```csharp
context.Request.Headers.GetValueOrDefault("header-name", "").Equals("expected-header-value", StringComparison.OrdinalIgnoreCase)
```

--------------------------------

### Check URI Parameter Existence

Source: https://github.com/azure/api-management-policy-snippets/blob/master/policy-expressions/README.md

Verifies if a specific URI parameter exists in the request.

```csharp
context.Request.MatchedParameters.ContainsKey("parameter-name") == true
```

--------------------------------

### Check HTTP Header Existence

Source: https://github.com/azure/api-management-policy-snippets/blob/master/policy-expressions/README.md

Verifies if a specific HTTP header exists in the request.

```csharp
context.Request.Headers.ContainsKey("header-name") == true
```

--------------------------------

### Generate Base64 Random Bytes in Bash

Source: https://github.com/azure/api-management-policy-snippets/blob/master/examples/oauth-proxy/readme.md

Use this bash command to generate Base 64 encoded random bytes for encryption keys.

```bash
openssl rand -base64 32
```

--------------------------------

### Check Query String Parameter Existence

Source: https://github.com/azure/api-management-policy-snippets/blob/master/policy-expressions/README.md

Verifies if a specific query string parameter exists in the request.

```csharp
context.Request.Url.Query.ContainsKey("parameter-name") == true
```

--------------------------------

### Check if Client Certificate is Uploaded in APIM

Source: https://github.com/azure/api-management-policy-snippets/blob/master/policy-expressions/README.md

Determines if the currently presented client certificate (by thumbprint) has been uploaded to API Management.

```csharp
context.Deployment.Certificates.Any(c => c.Value.Thumbprint == context.Request.Certificate.Thumbprint) == true
```

--------------------------------

### Check Policy Variable Value

Source: https://github.com/azure/api-management-policy-snippets/blob/master/policy-expressions/README.md

Compares the value of a policy variable (assumed string) against an expected string, ignoring case. Returns true if they match or if the variable is not present and the default empty string matches.

```csharp
context.Variables.GetValueOrDefault<string>("variable-name","").Equals("expected-value", StringComparison.OrdinalIgnoreCase)
```

--------------------------------

### OAuth Proxy Callback Policy

Source: https://github.com/azure/api-management-policy-snippets/blob/master/examples/oauth-proxy/readme.md

This policy handles an Identity Provider's callback in response to a sign-in request. Configure it as the 'callback' operation within an API called 'OAuth'.

```xml
<policies>
    <inbound>
        <base />
        <!-- Callback policy -->
        <oauth-proxy-callback />
    </inbound>
</policies>
```

--------------------------------

### Read JWT Claim

Source: https://github.com/azure/api-management-policy-snippets/blob/master/policy-expressions/README.md

Extracts a specific claim value from a JWT found in the Authorization header. It assumes the token is Bearer type and correctly formatted.

```csharp
context.Request.Headers.GetValueOrDefault("Authorization")?.Split(' ')?[1].AsJwt()?.Claims["claim-name"].FirstOrDefault()
```

--------------------------------

### OAuth Proxy Sign-out Policy

Source: https://github.com/azure/api-management-policy-snippets/blob/master/examples/oauth-proxy/readme.md

This policy clears a user's session cookie and removes all token data from the cache. Configure it as the 'signout' operation within an API called 'OAuth'.

```xml
<policies>
    <inbound>
        <base />
        <!-- Sign-out policy -->
        <oauth-proxy-sign-out />
    </inbound>
</policies>
```

--------------------------------

### Add Property to JSON Body

Source: https://github.com/azure/api-management-policy-snippets/blob/master/policy-expressions/README.md

Adds a new property to the request's JSON body. The modified JSON is returned as a string.

```csharp
JObject body = context.Request.Body.As<JObject>(); 
body.Add(new JProperty("property-name", "property-value")); 
return body.ToString();
```

=== COMPLETE CONTENT === This response contains all available snippets from this library. No additional content exists. Do not make further requests.