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The Mex feature provides access to WhatsApp’s Meta Exchange (MEX) GraphQL API, enabling queries and mutations for advanced operations.

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Access

Access MEX operations through the client: 
let mex = client.mex();

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Methods

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query

Execute a GraphQL query. 
pub async fn query(&self, request: MexRequest<'_>) -> Result<MexResponse, MexError>
Parameters:
  • request - A MexRequest containing the document ID and variables
Returns:
  • MexResponse - The GraphQL response with data and/or errors
Example: 
use serde_json::json;
use whatsapp_rust::MexRequest;

let request = MexRequest {
    doc_id: "29829202653362039",
    variables: json!({
        "user_ids": ["15551234567@s.whatsapp.net"]
    }),
};

let response = client.mex().query(request).await?;

if response.has_data() {
    let data = response.data.unwrap();
    println!("Result: {:?}", data);
}

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mutate

Execute a GraphQL mutation. 
pub async fn mutate(&self, request: MexRequest<'_>) -> Result<MexResponse, MexError>
Parameters:
  • request - A MexRequest containing the document ID and variables
Returns:
  • MexResponse - The GraphQL response with data and/or errors
Example: 
use serde_json::json;
use whatsapp_rust::MexRequest;

let request = MexRequest {
    doc_id: "mutation_doc_id_here",
    variables: json!({
        "input": {
            "field": "value"
        }
    }),
};

let response = client.mex().mutate(request).await?;

if let Some(errors) = &response.errors {
    for error in errors {
        eprintln!("Error: {}", error.message);
    }
}

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Types

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MexRequest

Request structure for GraphQL operations. 
pub struct MexRequest<'a> {
    /// GraphQL document ID
    pub doc_id: &'a str,
    /// Query variables as JSON
    pub variables: serde_json::Value,
}

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MexResponse

Response from a GraphQL operation. 
pub struct MexResponse {
    /// Response data (if successful)
    pub data: Option<serde_json::Value>,
    /// List of errors (if any)
    pub errors: Option<Vec<MexGraphQLError>>,
}
Methods:
  • has_data() - Returns true if response contains data
  • has_errors() - Returns true if response contains errors
  • fatal_error() - Returns the first fatal error, if any

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MexGraphQLError

GraphQL error structure. 
pub struct MexGraphQLError {
    /// Error message
    pub message: String,
    /// Error extensions with additional details
    pub extensions: Option<MexErrorExtensions>,
}
Methods:
  • error_code() - Returns the error code if available
  • is_summary() - Returns true if this is a summary error (is_summary == true in extensions)
  • has_error_code() - Returns true if this error has an error code

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MexErrorExtensions

Additional error metadata. 
pub struct MexErrorExtensions {
    /// Numeric error code
    pub error_code: Option<i32>,
    /// Whether this is a summary error
    pub is_summary: Option<bool>,
    /// Whether the operation can be retried
    pub is_retryable: Option<bool>,
    /// Error severity level
    pub severity: Option<String>,
}

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Error handling

The MexError enum covers all possible error cases: 
pub enum MexError {
    /// Payload parsing error
    PayloadParsing(String),
    /// Extension error with code and message
    ExtensionError { code: i32, message: String },
    /// IQ request failed
    Request(IqError),
    /// JSON serialization/deserialization error
    Json(serde_json::Error),
}
Example: 
match client.mex().query(request).await {
    Ok(response) => {
        if let Some(fatal) = response.fatal_error() {
            eprintln!("Fatal error: {} (code: {:?})", 
                fatal.message, 
                fatal.error_code()
            );
        } else if response.has_data() {
            println!("Success: {:?}", response.data);
        }
    }
    Err(MexError::ExtensionError { code, message }) => {
        eprintln!("MEX error {}: {}", code, message);
    }
    Err(e) => eprintln!("Request failed: {}", e),
}

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Response handling

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Check for data

let response = client.mex().query(request).await?;

if response.has_data() {
    let data = response.data.unwrap();
    // Process data
}

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Handle non-fatal errors

let response = client.mex().query(request).await?;

if response.has_errors() {
    for error in response.errors.as_ref().unwrap() {
        if !error.is_summary() && !error.has_error_code() {
            // Non-fatal: log warning but continue
            eprintln!("Warning: {}", error.message);
        }
    }
}

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Extract typed data

use serde::Deserialize;

#[derive(Deserialize)]
struct UserResult {
    jid: String,
    country_code: String,
}

let response = client.mex().query(request).await?;

if let Some(data) = response.data {
    let users: Vec<UserResult> = serde_json::from_value(
        data["xwa2_fetch_wa_users"].clone()
    )?;
    
    for user in users {
        println!("User {} from {}", user.jid, user.country_code);
    }
}